Pollution – Just Facts

* This research is based upon the most recent available data in 2012. All graphs show the full range of available data, and all facts are cited based upon availability and relevance, not to slant results by singling out specific years that are different from others.

* A small amount of a given pollutant confined to a small area may cause harm, while a far larger amount of the same pollutant dispersed over a large area can be harmless.[2] [3] A "fundamental principle" of toxicology is "the dose makes the poison."[4]

Anything is toxic at a high enough dose. … Even water, drunk in very large quantities, may kill people by disrupting the osmotic balance in the body's cells. … Potatoes make the insecticide, solanine. But to ingest a lethal dose of solanine would require eating 100 pounds (45.4 kg) of potatoes at one sitting. However, certain potato varieties – not on the market – make enough solanine to be toxic to human beings. Generally, potentially toxic substances are found in anything that we eat or drink.[5]

* With regard to respiration, even oxygen can be toxic when breathed in high concentrations.[6]

* In addition to a substance's chemical structure and dosage, other factors that affect its toxicity include (but are not limited to) the duration of exposure, the route of exposure (e.g., skin contact, inhalation, ingestion), and the physiology of the exposed organisms.[7] [8] [9]

The factors driving your concept of risk—emotion or fact—may or may not seem particularly important to you, yet they are. The risks you are willing to assume and the experiences or products you avoid because of faulty assumptions and misinformation affect the quality of your life and the lives of those around you. Thus, even though it may be tempting to let misperceptions and emotions shape your ideas about risky products and activities, there are risks in misperceiving risks.[10]

* For facts about carbon dioxide (the primary man-made greenhouse gas), visit Just Facts' research on global warming.

* The United States Environmental Protection Agency (EPA) monitors the outdoor (ambient) concentrations of six major air pollutants on a nationwide basis. These are called "criteria pollutants."[11] [12] [13]

* Under federal law, criteria pollutants are those that are deemed by the administrator of the EPA to be widespread and to "cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare…."[14] [15] [16]

* The six criteria pollutants are carbon monoxide, ground-level ozone, lead, nitrogen dioxide, particulate matter, and sulfur dioxide.[17]

* The EPA administrator is required by law to establish "primary" air quality standards for criteria pollutants that are "requisite to protect the public health" with "an adequate margin of safety…."[18] [19]

* The EPA administrator is also required to establish "secondary" air quality standards "requisite to protect the public welfare," a term that includes "animals, crops, vegetation, and buildings."[20] [21]

* For some criteria pollutants, the EPA has established a single criterion as the primary and secondary air quality standard. In other cases, the EPA has established up to two different criteria as primary air quality standards and up to two different criteria as secondary air quality standards.[22]

* Per an EPA summary of laws and court decisions relevant to the process of setting air quality standards:

The selection of any particular approach to providing an adequate margin of safety is a policy choice left specifically to the Administrator's judgment. …

In setting primary and secondary standards that are "requisite'' to protect public health and welfare … EPA's task is to establish standards that are neither more nor less stringent than necessary for these purposes. In so doing, EPA may not consider the costs of implementing the standards.[23] [24]

* The administrator of the EPA is appointed by the president, contingent upon the approval of a majority vote in the Senate.[25] [26]

* Gasoline-powered vehicles account for roughly 86% of manmade CO emissions in the U.S. Other major sources include stationary items that burn fuel such as power plants and home heaters (6%), industrial processes (3%), and fires (2%).[28] [29] [30] [31]

* Ambient CO concentrations typically peak near roadways and during the times of the day when commuting is heaviest.[32]

* The population most susceptible to elevated CO levels are those with coronary artery disease.[33] Coronary artery disease is typically caused by the build-up of cholesterol-containing deposits in major arteries.[34]

* The primary study used by the EPA to set clean air standards for CO was conducted on subjects with moderate to severe coronary artery disease, more than half of whom previously had heart attacks. To establish a baseline, participants engaged in mild exercise on a treadmill while measurements were made of the time it took to develop chest pain and a specific electrocardiogram signal that indicates insufficient oxygen supply to the heart. Subjects repeated this test after resting for about an hour while being exposed to elevated CO levels ranging from 42 to 202 parts per million (mean of 117). After exposure, the amount of time spent exercising before the onset of chest pain decreased by 4.2%, and the amount of time spent exercising before this specific electrocardiogram signal emerged decreased by 5.1%.[35] [36]

* An EPA primary clean air standard for carbon monoxide is an 8-hour average of 9 parts per million (ppm), not to be exceeded more than once per year.[37] [38] From 1980 through 2010, the average U.S. ambient carbon monoxide level decreased by 82% as measured by this standard:

* All of the U.S. population live in counties that meet the EPA's clean air standards for carbon monoxide.[41] [42] Per the EPA, a "large proportion" of monitoring sites have CO levels that are below the limit that conventional instruments can detect (1 ppm).[43]

• "is not usually emitted directly into the air" but is formed "by a chemical reaction between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight."[45]

• "can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma. Ground level ozone also can reduce lung function and inflame the linings of the lungs. Repeated exposure may permanently scar lung tissue."[46]

* Gasoline-powered vehicles account for roughly 62% of manmade nitrogen oxides emissions in the U.S. Other major sources include stationary items that burn fuel (30%) and industrial processes (7%).[47] [48]

* Gasoline-powered vehicles account for roughly 45% of manmade volatile organic compound emissions in the U.S. Other major sources include solvents (23%), industrial processes (18%), stationary items that burn fuel (4%).[49] [50]

* The populations most susceptible to elevated ozone levels are children, the elderly, people with lung disease, and people who are active outdoors.[51] [52]

* Ambient ozone concentrations typically peak on hot sunny days in urban areas.[53] [54] Per the EPA:

• Ozone concentrations generally rise with increasing elevation, and "since O3 monitors are frequently located on rooftops in urban settings, the concentrations measured there may overestimate the exposure to individuals outdoors in streets and parks, locations where people exercise and their maximum O3 exposure is more likely to occur."

• A study performed in Boston found that "ambient O3 levels overestimated personal exposures 3- to 4-fold in the summer and 25-fold in the winter."

• "Using ambient concentrations to determine exposure generally overestimates true personal O3 exposures … by approximately 2- to 4- fold…."

• "The use of central ambient monitors to estimate personal exposure has a greater potential to introduce bias since most people spend the majority of their time indoors, where O3 levels tend to be much [about 10 times] lower than outdoor ambient levels."[55]

* The EPA's primary and secondary clean air standard for ozone is 0.075 parts per million (ppm) as measured by a 3-year average of the fourth-highest daily maximum 8-hour concentration per year.[56] [57] From 1980 through 2010, the average U.S. ambient ozone level decreased by 27% as measured by this standard:

* As of 2010, about 35% of the U.S. population live in counties that do not meet the EPA's clean air standards for ozone.[60]

* Lead (Pb) is a metallic element that can be released as particles into the air. These airborne particles can be directly inhaled, or they can settle out of the air into water and food supplies, and thus be ingested orally.[61] Lead can accumulate in the human body over extended periods, resulting in a condition known as "cumulative poisoning." This can impair cognitive ability and cause conditions such as high blood pressure and kidney dysfunction.[62] [63]

* Gasoline-powered vehicles account for roughly 58% of manmade lead emissions in the U.S. Other major sources include industrial processes (25%) and stationary items that burn fuel (15%).[64] [65] [66] [67]

* Ambient lead concentrations typically peak near mines, busy roadways, and factories that melt or fuse lead.[68]

* The population most susceptible to elevated lead concentrations is children. Effects can include behavioral disorders, learning deficits, and lowered IQ.[69] [70] The EPA set the clean air standard for lead with the goal of precluding a mean IQ loss of more than one or two points among children exposed to this threshold.[71]

* The EPA's primary and secondary clean air standard for lead is a rolling 3-month average of 0.15 micrograms per meter (μg/m³).[72] From 1980 through 2010, the average U.S. ambient lead level decreased by 89% as measured by this standard:

* As of 2010, about 7% of the U.S. population live in counties that do not meet the EPA's clean air standards for lead.[75]

* Nitrogen dioxide (NO2) is a highly reactive gas that can cause respiration problems.[76] [77]

* Ambient NO2 concentrations typically peak near roadways. Per the EPA, NO2 monitors are "not sited to measure peak roadway-associated NO2 concentrations," and thus, "individuals who spend time on and/or near major roadways could experience NO2 concentrations" that are 30% to 100% higher than monitors in that general area indicate.[80]

* The populations most susceptible to elevated NO2 levels are asthmatics and children.[81]

* An EPA primary and secondary clean air standard for nitrogen dioxide is an annual average of 53 parts per billion (ppb).[82] From 1980 through 2010, the average U.S. ambient nitrogen dioxide decreased by 52% as measured by this standard:

* All of the U.S. population live in counties that meet this EPA clean air standard for nitrogen dioxide.[85]

* In 2010, the EPA created a new primary NO2 standard that supplements the preexisting standard. It is intended to provide increased protection against health effects associated with short-term exposures, as opposed to the preexisting standard, which is based on the average annual exposure.[86] [87] It may be 2016 before the EPA is able to determine which counties meet the new standard.[88]

is a complex mixture of extremely small particles and liquid droplets … made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.

The size of particles is directly linked to their potential for causing health problems. EPA is concerned about particles that are 10 micrometers [μm] in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects.[89] [90]

* The EPA monitors the ambient concentrations of two major categories of particulate matter:

• PM2.5, which are 2.5 μm and smaller (no larger than 1/28th the diameter of a human hair). These are also called "fine particles" and are mainly produced by combustion and other chemical reactions.

• PM10, which are 10 μm and smaller (no larger than 1/7th the diameter of a human hair). These are also called "thoracic coarse particles" and are mainly produced by mechanical processes such as mining and road work.[91] [92]

* The EPA has itemized numerous methods to control PM emissions including paving unpaved roads, swapping out wood-burning stoves for propane logs, and installing particle filters/collection devices on engines and factories.[93] [94] [95]

* The populations most susceptible to elevated PM levels are individuals with heart and lung diseases, the elderly, and children.[96]

* Dust accounts for roughly 78% of manmade PM10 emissions in the U.S. Other major sources include stationary items that burn fuel (6%), agriculture (5%), industrial processes (4%), gasoline-powered vehicles (3%), and fires (1%).[97] [98]

* The EPA's primary and secondary clean air standard for PM10 is a 24-hour mean of 150 micrograms per cubic meter (μg/m³), not to be exceeded more than once per year on average over 3 years.[99] From 1990 through 2010, the average U.S. ambient PM10 level decreased by 38% as measured by this standard:

* As of 2010, about 2% of the U.S. population live in counties that do not meet the EPA's clean air standards for PM10.[102]

* Dust accounts for roughly 34% of manmade PM2.5 emissions in the U.S. Other major sources include stationary items that burn fuel (25%), gasoline-powered vehicles (12%), industrial processes (9%), agriculture (4%), and fires (4%).[103] [104]

* An EPA primary and secondary clean air standard for PM2.5 is an annual mean of 15 micrograms per cubic meter (μg/m³), averaged over 3 years.[105] From 2000 through 2010, the average U.S. ambient PM2.5 level decreased by 27% as measured by this standard:

* As of 2010, about 6% of the U.S. population live in counties that do not meet the EPA's clean air standards for PM2.5.[109]

* Sulfur dioxide (SO2) is a highly reactive gas that can cause respiration problems.[110] [111]

* Stationary items that burn fuel account for roughly 85% of manmade sulfur dioxide emissions in the U.S. Other major sources include industrial processes (8%) and gasoline-powered vehicles (7%).[112] [113] [114]

* The population most susceptible to elevated SO2 levels is asthmatics. Among healthy non-asthmatics, SO2 does not typically affect lung function until concentrations exceed 1,000 parts per billion (ppb). Among asthmatics engaged in exercise, exposure to SO2 concentrations ranging from 200-300 ppb for 5-10 minutes have been shown to decrease lung function in 5-30% of these individuals.[115]

* Until 2010, an EPA primary clean air standard for sulfur dioxide was an annual mean of 30 ppb.[116] From 1980 through 2010, the average U.S. ambient sulfur dioxide level decreased by 79% as measured by this standard:

* In 2010, about 5% of the U.S. population lived in counties that did not meet the EPA's clean air standards for sulfur dioxide.[119]

* In 2010, the EPA created a new primary SO2 standard that is "substantially more stringent than the previous standards." It is intended to provide increased protection against health effects associated with short-term exposures. It may be 2016 before the EPA is able to determine which counties meet the new standard.[120] [121]

* After tobacco smoke, the second leading cause of lung cancer in the U.S. is radon, a gas that arises from the decay of natural uranium, which is common in rocks and soils.[122]

* The EPA estimates that 14.4 percent of lung cancer deaths in the U.S. are related to radon.[123]

* Radon typically seeps up from the ground into houses via floors and walls. In houses with radon levels at or above 4 picocuries per liter of air (pCi/L), the EPA recommends taking mitigation actions.[124]

* As of 2009, roughly 930,000 U.S. homes have radon mitigation systems, and about 7,120,000 homes have radon levels that reach or exceed 4 pCi/L and don't have mitigation systems. This amounts to about 6.1% of all U.S. households.[125] [126]

* Water has a pH of 7 (neutral on the pH scale), but various natural and manmade substances in the atmosphere can combine with water to change its pH level. When rainwater has a pH lower than 5.0-5.6, it is considered acid rain.[127] [128]

* Acid rain can harm lakes, streams, aquatic life, buildings, crops, and forests.[129] [130]

* Likewise, the EPA's "Plain English Guide to the Clean Air Act" states that "sulfur dioxide (SO2) and nitrogen oxides (NOx) are the principal pollutants that cause acid precipitation" and attributes these emissions strictly to manmade sources.[132]

* A study published in the journal Nature in 2003 found that certain types of trees, which were thought to absorb more NOx than they emitted, actually emit more NOx than they absorb. Previous studies had underestimated these natural NOx emissions because scientists had failed to replicate natural conditions by exposing the trees to ultraviolet light. Based upon the results of a new study conducted under natural conditions, the study's authors estimated that coniferous trees (such as spruce, fir, and pine) in the northern hemisphere may emit "comparable" amounts of NOx to "those produced by worldwide industrial and traffic sources."[133] [134] [135]

* A 1989 paper in the journal Hydrobiologia faults "human activities" for the fact that "annual precipitation averages less than pH 4.5 over large areas of the Northern Temperate Zone, and not infrequently, individual rainstorms and cloud or fog-water events have pH values less than 3."[136]

* Formic acid, an organic compound emitted by natural processes and human activities, can contribute to the acidity of rain, but it is not associated with the harmful effects of acid rain because it rapidly decomposes.[137] [138] [139]

* An academic text published in 2002 asserts that formic acid contributes "slightly" to rainwater acidity.[140]

* A December 2011 paper published in Nature Geoscience estimated based upon satellite measurements and computer models that:

• formic acid accounts for 30–50% of the summertime rainwater acidity "over much of the US."

• 90% of atmospheric formic acid is emitted by natural sources (primarily forests).[141] [142]

* Nitrogen oxides are one of the two primary ozone precursors.[143] A study published in the journal Nature in March 2003 estimated that coniferous forests in the northern hemisphere may emit "comparable" amounts of nitrogen oxides to "those produced by worldwide industrial and traffic sources."[144] [145] [146]

* Ozone concentrations in relatively remote U.S. wilderness areas often reach 0.050 ppm to 0.060 ppm, particularly at high-altitude locations. The EPA states that it is "impossible to determine" the causes of these elevated ozone levels using currently available data, but based upon computer models, the EPA attributes these high levels to a combination of natural ozone precursors, manmade ozone and precursors being transported by winds, and natural ozone in the upper atmosphere seeping down to ground level.[149]

* The EPA estimates that natural ground-level ozone concentrations in the continental U.S. are roughly 0.015 ppm to 0.035 ppm and are typically less than 0.025 ppm "under conditions conducive to high O3 episodes." Five other studies have produced results ranging from 0.020 ppm to 0.045 ppm.[150] The range of results from these six studies corresponds to natural ozone background levels that vary from 20% to 60% of the EPA's clean air standard.[151]

* For a study published in the journal Nature in July 2003, scientists compared the growth of trees in New York City to genetically identical trees in surrounding suburban and rural areas. Contrary to expectations, the trees in the city grew about twice as fast as those in the rural areas. The study's lead author stated, "No matter what soil I grew them in, they always grew twice as large in New York City. … In the country, the trees were about up to my waist. In the city, they were almost over my head—it's really dramatic."

Experiments performed for this study showed that higher ozone levels in the rural areas negatively impacted the trees' growth rates. Although the city had higher peak ozone levels than the rural areas, the rural areas had higher long-term average levels than the city. The study's authors attributed these higher rural ozone levels to manmade ozone precursors blowing in from the city and to a "scavenging reaction" that limits ozone levels in urban areas. The authors did not address the prospect that higher ozone levels in rural areas were related to natural sources.[152] [153] [154]

* On average, Americans spend 87% of their time indoors, 8% outdoors, and 6% in vehicles.[155]

* Indoor levels of ozone are typically one-tenth that of outdoor levels. This is because ozone is removed from the air by interactions with surfaces such as walls, carpeting, and furnishings.[156]

* Lead exposure can often be higher in homes than outdoors, and even greater lead exposures can occur in office buildings, older homes with lead paint, and homes of smokers.[157]

* Carbon monoxide levels in vehicles are typically 2-5 times higher in vehicles than outdoors. These levels generally decline as traffic volume declines and as speed increases.[158]

* Carbon monoxide levels are generally higher in homes than outdoors, and even greater levels of CO have been measured in rooms where people are smoking, indoor ice rinks (from ice resurfacing machines), homes with attached garages in which cars are idled, and indoor arenas where motocross races and tractor pulls are held.[159]

* In addition to criteria pollutants, the EPA is required by law to regulate the emissions of substances that

present, or may present, through inhalation or other routes of exposure, a threat of adverse human health effects (including, but not limited to, substances which are known to be, or may reasonably be anticipated to be, carcinogenic, mutagenic, teratogenic, neurotoxic, which cause reproductive dysfunction, or which are acutely or chronically toxic) or adverse environmental effects…."[160] [161]

* These substances are called hazardous air pollutants (HAPs) or toxic air pollutants.[162]

* Unlike criteria pollutants, the law requires the EPA to consider the costs of enacting regulations to control the emissions of HAPs.[163] [164]

* Unlike criteria pollutants, ambient HAP levels are not monitored on a nationwide basis.[165] [166] Instead, the EPA estimates the annual emissions of these pollutants.[167]

* The EPA currently regulates 188 HAPs and has singled out five of them that are "believed to account for the greatest health risks…." These are acrolein, benzene, 1,3-butadiene, ethylene dibromide, and hydrazine.[168] [169]

* Between a baseline period of 1990-1993 and 2005,[170] the combined annual emissions of all hazardous air pollutants decreased by 42%.[171] [172] During this same timeframe, the annual emissions of the five HAPs believed to account for the greatest health risks fell by the following amounts:

• wetlands, which are "areas that are periodically saturated or covered by water"[174];

• coastal waters, which border the open ocean and include areas such as estuaries, coastal wetlands, seagrass meadows, coral reefs, and kelp forests[175] [176]; and

• aquifers, which are underground beds of porous rock, sediment, or soil that store water.[177]

* Some pollutants accumulate within living organisms in greater concentrations than in their surrounding environments. This is called bioaccumulation, and it occurs because certain pollutants are not easily excreted or metabolized.[178]

* Bioaccumulative substances are often passed upwards through aquatic food chains, and thus, concentrations of such chemicals tend to be higher in creatures near the top of these food chains, such as salmon and trout.[179] [180]

* PCB's are a group of bioaccumulative chemicals that were banned from production in the U.S. in 1979. Due to bioaccumulation, the concentrations of PCBs in fish can range from 2,000 to more than 1,000,000 times higher than the ambient concentrations in waters that the fish inhabit.[181]

* Dioxins are a group of highly toxic bioaccumulative chemicals that are sometimes released through incineration, combustion, and other processes. Due to bioaccumulation, the concentrations of dioxins in fish can range from hundreds to thousands of times higher than the ambient concentrations in waters that the fish inhabit.[182]

* During 2000 through 2003, the EPA conducted a random survey of fish contamination levels in 500 of the 147,000 lakes and reservoirs in the continental United States. The EPA tested bottom-dwelling and predator fish for 268 chemicals that bioaccumulate. The study found that:

• in the filets of predators, the EPA's human health limits for the five chemicals that account for 97% of fish consumption advisories were exceeded as follows:

Chemical	EPA's limit for four 8-ounce fish meals per month	Portion of water bodies with fish exceeding this limit
mercury	300 parts per billion	48.8%
PCBs	12 parts per billion	16.8%
dioxins	0.15 parts per trillion	6.6%
DDT	69 parts per billion	1.7%
chlordane	67 parts per billion	0.3%

* During 2003 through 2006, the EPA conducted a random survey of fish contamination levels at 1,623 locations in coastal waters throughout the continental United States, Southeastern Alaska, American Samoa, and Guam. The EPA tested bottom-dwelling and slower-moving fish (such as shrimp, lobsters, and finfish) for 16 chemical contaminants such as inorganic arsenic, cadmium, and PCBs. The study found that fish did not exceed the EPA's four-meal-per-month contamination limits for any of these chemicals:

* Roughly 13% of U.S. surface waters do not meet state fecal bacteria limits for various uses such as recreation and public water supplies. A technology called microbial source tracking (MST) allows scientists to trace the sources of fecal bacteria. A 2005 EPA report summarizes eight studies conducted in various localities with elevated levels of fecal bacteria.[192] [193] The results were as follows:

• St. Andrews Park on Jekyll Island – The dominant source was wild birds.[194]

• Vermillion River (Minnesota) – In descending order, the dominant sources were geese, pigs, cats, cows, humans, deer, sheep, and turkeys.[196]

• Anacostia River (Maryland/District of Columbia) – In descending order, the dominant sources were birds (31%), wildlife (25%), humans (24%), and pets (20%).[197]

• Accotink Creek, Blacks Run, and Christians Creek (Virginia) – The dominant sources were waterfowl, humans, pets, livestock, and poultry.[198] [199]

• Avalon Bay (California) – The dominant sources were birds, "contaminated subsurface water, leaking drains, and runoff from street wash-down activities."[200]

• Holmans Creek (Virginia) – The dominant sources were humans and cattle.[201]

* The amount of fresh water that resides under the surface of the earth is roughly 30 times greater than the world's fresh surface waters. Such ground water feeds natural springs and streams and is used by humans for drinking, cleaning, agriculture, and industry.[203]

* Federal law requires that public water systems be tested for various contaminants and treated (if needed) to meet these standards. In 2007, 92% of public water system customers were served by facilities that had no reported violations of the EPA's health-based drinking water standards.[204] A caveat of this finding is that violations are reported by states, and the EPA has found cases in which violations were not reported.[205]

* Per a 2006 EPA report, "very little" lead in drinking water comes from water utilities. Instead, it primarily comes from indoor plumbing in public schools, apartments, and houses.[206]

* Private wells are not regulated under federal law and, in most cases, they are not regulated under state law. During 1991-2004, the U.S. Geological Survey (USGS) measured contamination levels in 2,167 private wells used for household drinking water. The wells were tested for 214 manmade and natural contaminants such as pesticides, radon, fecal bacteria, and nitrate. The results were as follows:

• About 23% of wells had at least one contaminant with a concentration that exceeded either an EPA or USGS health benchmark.

• "No individual contaminant was present in concentrations greater than available health benchmarks in more than 8 percent of the sampled wells."

• Other than nitrate and fecal bacteria, the most frequent contaminants that exceeded health benchmarks derive strictly from natural sources.

• Manmade organic compounds (such as pesticides) exceeded health benchmarks in 0.8 percent of wells.[207]

* In agricultural areas, about 1% of private wells have pesticide levels that exceed human health benchmarks.[208]

Many people are frightened by the use of synthetic chemicals on food crops because they have heard that these chemicals are "toxic" and "cancer causing," but are all synthetic chemicals more harmful than substances people readily ingest, like coffee and soft drinks? No…. For example, in a study to assess the toxicities of various compounds, half of the rats died when given 233 mg of caffeine per kg of body weight, but it took more than 10 times that amount of glyphosate … which is the active ingredient in the herbicide Roundup, to cause the same percentage of deaths as 233 mg of caffeine.[209]

* Municipal solid waste, also known as trash or garbage, consists of nonhazardous items that are thrown away, such as newspapers, cans, bottles, packaging, clothes, furniture, food scraps, and grass clippings.[210] [211] Municipal solid waste does not include industrial, hazardous, or construction waste.[212]

* The most common types of municipal solid waste (by weight) are paper (28.5%), food scraps (13.9%), yard trimmings (13.4%), plastics (12.4%), metals (9.0%), rubber, leather and textiles (8.4%), wood (6.4%), glass (4.6%), and other materials (3.4%).[213]

* In 2010, roughly 55% to 65% of municipal solid waste was generated by residences, while 35% to 45% was generated by businesses and institutions (like hospitals and schools).[214]

* In 2010, Americans generated about 250 million tons of trash or 4.43 pounds per person per day.[215] Of this, 54% was placed in landfills, 26% was recycled, 12% was burned for energy, and 8% was composted.[216]

* Older landfills were often malodorous, pest-ridden, and laden with noxious pollutants. Modern landfills seldom have such problems and operate under regulations that require controls over the types of refuse that can be buried, a daily covering of dirt over the refuse, composite liners, clay caps, and runoff collections systems. Many modern landfills generate energy by collecting and burning methane from decomposing organic materials.[217] [218] [219] [220]

* The average lifecycle of a landfill is about 30-50 years.[221] After this, landfills must be covered and can be used for purposes such as parks, commercial development, golf courses, nature conservatories, ski slopes, and airfields. Hazardous waste dumps can also be used for such purposes.[222] [223] [224] [225]

* The Fresh Kills landfill in Staten Island, New York, serviced New York City from 1948-2001 and is now being converted into a park. It contains five mounds of fill, ranging from 90 to 225 feet.[226] [227]

* At the current U.S. population growth rate and the current per-person trash production rate, the U.S. will use about 13.6 billion cubic yards of municipal landfill volume over the next 50 years. Given a landfill height of 90 feet, this equates to a square area that is 12.1 miles long on each side or four one-thousandths of one percent (0.0041%) of the country's land area:

* In 2010, Americans recycled about 26% of solid municipal waste or 1.2 pounds per person per day.[229]

* Factors that affect the environmental impacts and financial costs associated with recycling include (but are not limited to):

• the mining, harvesting, and manufacturing of virgin materials that are recyclable,

• the manufacturing and operation of separate collection trucks for curbside recycling programs,

• the post-collection sorting and transportation of recyclables to manufacturing facilities,

• the location of pollution emitted from the above processes (for example, pollution from curbside recycling trucks is mostly emitted in populated areas where many people are affected and where pollution levels are already high).[232] [233] [234] [235]

* Factors that determine the financial costs and environmental impacts associated with manufacturing from virgin materials and disposal in landfills include (but are not limited to):

* In the mid-1970s, the EPA concluded that recycling generally produces less pollution than manufacturing from virgin materials.[238]

• the EPA's generalization about the environmental benefits of recycling "does not necessarily hold true in all cases."

• "it is usually not clear whether secondary manufacturing [recycling] produces less pollution per ton of material processed than primary manufacturing."

• with paper recycling, "5 toxic substances 'of concern' were found only in virgin processes and 8 were found only in recycling processes; of 12 pollutants found in both processes, 11 were present in higher levels in the recycling processes."[239]

* Environmental impact assessments of curbside recycling have produced conflicting results, such as these:

• A study performed for a 1999 paper in the Journal of Environmental Engineering found that:

- "some recycling improves environmental quality and sustainability, whereas other recycling has the opposite effect."

- "for most communities, curbside recycling is only justifiable for some postconsumer waste, such as aluminum and other metals."

- "curbside recycling of postconsumer metals can save money and improve environmental quality if the collection, sorting, and recovery processes are efficient. Curbside collection of glass and paper is unlikely to help the environment and sustainability save in special circumstances."[240]

• A study performed for a 2005 paper in the International Journal of Life Cycle Assessment found that:

- "recycling of newspaper, cardboard, mixed paper, glass bottles and jars, aluminum cans, tin-plated steel cans, plastic bottles, and other conventionally recoverable materials found in household and business municipal solid wastes consumes less energy and imposes lower environmental burdens than disposal of solid waste materials via landfilling or incineration, even after accounting for energy that may be recovered from waste materials at either type disposal facility."

- "recycling is environmentally preferable to disposal by a substantial margin."[241]

* Both of the studies cited above (and others) conclude that without governmental subsidies or mandates, curbside recycling is generally more expensive than conventional disposal and manufacturing. The recycling of products made of aluminum is an exception to this generality.[242] [243] [244] [245]

* Various state and local governments have enacted laws and quotas that require mandatory recycling.[246] Examples of such include the states of North Carolina,[247] New Jersey,[248] and Connecticut,[249] the cities of Seattle,[250] San Francisco,[251] and New York,[252] 168 municipalities in Massachusetts,[253] and Monroe County, New York.[254]

* Various nations, localities, and businesses have banned or imposed taxes and surcharges on disposable plastic supermarket bags. Example of such include China,[255] Ireland,[256] Seattle, San Francisco, Westport, Connecticut,[257] Washington, DC,[258] and Whole Foods.[259]

* A 2011 study published by the United Kingdom's Environment Agency evaluated nine categories of environmental impacts caused by different types of supermarket bags, such as plastic, degradable plastic, paper, and reusable cotton totes. The study quantified "all significant life cycle stages from raw material extraction, through manufacture, distribution use and reuse to the final management of the carrier bag as waste."[260] The study found:

• "The environmental impact of carrier bags is dominated by resource use and production. Transport, secondary packaging and end-of-life processing generally have a minimal influence on their environmental performance."

• "The manufacturing of the bags is normally the most significant stage of the life cycle, due to both the material and energy requirements. The impact of the energy used is often exacerbated by their manufacture in countries where the electricity is produced from coal-fired power stations."

• "Reusing lightweight [plastic] carrier bags as bin liners [trash bags] produces greater benefits than recycling bags due to the benefits of avoiding the production of the bin liners they replace."[261]

• The average supermarket shopper must use the same reusable totes the following number of times before they have less environmental impact in each of the following categories than the disposable plastic bags they replace:

Environmental Impact [183]	Times that the same tote must be reused to have less impact than disposable plastic bags
Environmental Impact [183]	Cotton tote (expected life is 52 reuses)	Plastic polypropylene tote (expected life is 104 reuses)
Global warming potential	172	14
Abiotic depletion	94	17
Acidification	245	9
Eutrophication	393	19
Human toxicity	314	14
Fresh water aquatic ecotoxicity	351	7
Marine aquatic ecotoxicity	354	11
Terrestrial ecotoxicity	1,899	30
Photochemical oxidation	179	10

* The study also found that paper bags and degradable plastic bags have a worse environmental impact than standard disposable plastic bags in all nine impact categories.[264]

[1] Entry: "pollution." The American Heritage Science Dictionary, Houghton Mifflin, 2005. Page 495.

[2] Book: Chemical Exposure and Toxic Responses. Edited by Stephen K. Hall, Joana Chakraborty, and Randall J. Ruch. CRC Press, 1997.

Pages 4-5: "The relationship between the dose of a toxicant and the resulting effect is the most fundamental aspect of toxicology. Many believe, incorrectly, that some agents are toxic and others are harmless. In fact, determinations of safety and hazard must always be related to dose. This includes a consideration of the form of the toxicant, the route of exposure, and the chronicity [time] of exposure."

[3] Book: Biological Risk Engineering Handbook: Infection Control and Decontamination. By Edited by Martha J. Boss and Dennis W. Day. CRC Press, 2003. Chapter 4: "Toxicology." By Richard C. Pleus, Harriet M. Ammann, R. Vincent Miller, and Heriberto Robles. Page 98:

The maximum dose that results in no adverse effects is called the threshold dose. The concept of threshold implies that concentrations of exposure present are so low that adverse effect cannot be measured. Some notable exceptions occur, such as when a person develops an allergic reaction to chemical (only specific chemicals are capable of causing allergic reactions).

Another exception, although controversial, is chemicals that cause cancer. Given our current lack of understanding of the mechanisms that lead to cancer initiation and development, regulatory agencies have adopted the position that any dose of a carcinogen has an associated risk of developing cancer. Scientifically, not all carcinogens are in fact capable of causing an effect at low doses; however, the problem is that no one knows what the dose must be in order to cause an effect, so to be safe the dose is set as low as practicable (usually at the limit of detection for instrumentation).

[4] Book: Molecular Biology and Biotechnology: A Guide for Teachers, Third edition. By Helen Kreuzer and Adrianne Massey. ASM [American Society for Microbiology] Press, 2008.

Page 540: "Paracelsus, a Swiss physician who reformed the practice of medicine in the 16th century, said it best: 'All substances are poisons, there is none which is not a poison. The dose differentiates a poison and a remedy.' This is a fundamental principle in modern toxicology: the dose makes the poison."

[5] Book: Understanding Environmental Pollution, Third edition. By Marquita K. Hill. Cambridge University Press, 2010. Pages 60, 62.

[6] Book: The Johns Hopkins Manual of Gynecology and Obstetrics, Third edition. Edited by Kimberly B. Fortner. Lippincott Williams & Wilkins, 2007. Chapter 38: "Critical Care." By Catherine D. Cansino and Pamela Lipsett.

Page 40: "The lungs are protected by a concentrated supply of endogenous antioxidants; however, when there is too much oxygen or not enough of the antioxidants, the lungs may be damaged, as in acute repository distress syndrome (ARDS). … Oxygen therapy with an F102 above 60% for longer than 48 hours is considered toxic.

[7] Book: Clinical Toxicology: Principles and Mechanisms. By Frank A. Barile. CRC Press, 2004.

Page 3: "What transforms a chemical into a toxin depends more on the length of time of exposure, dose (or concentration) of the chemical, or route of exposure, and less on the chemical structure, product formulation, or intended use of the material."

[8] Book: Biological Risk Engineering Handbook: Infection Control and Decontamination. By Edited by Martha J. Boss and Dennis W. Day. CRC Press, 2003. Chapter 4: "Toxicology." By Richard C. Pleus, Harriet M. Ammann, R. Vincent Miller, and Heriberto Robles. Page 98:

• Environmental factors and activity of the exposed subject (e.g., working habits, personal hygiene)

[9] Book: 1999 Toxics Release Inventory: Public Data Release. United States Environmental Protection Agency, April 2001.

Some high-volume releases of less toxic chemicals may appear to be a more serious problem than lower-volume releases of more toxic chemicals, when just the opposite may be true. For example, phosgene is toxic in smaller quantities than methanol. A comparison between these two chemicals for setting hazard priorities or estimating potential health concerns, solely on the basis of volumes released, may be misleading. …

The longer the chemical remains unchanged in the environment, the greater the potential for exposure. Sunlight, heat, or microorganisms may or may not decompose the chemical. … As a result, smaller releases of a persistent, highly toxic chemical may create a more serious problem than larger releases of a chemical that is rapidly converted to a less toxic form.

[10] Book: Molecular Biology and Biotechnology: A Guide for Teachers, Third edition. By Helen Kreuzer and Adrianne Massey. ASM [American Society for Microbiology] Press, 2008. Pages 540-541.

Six common air pollutants (also known as "criteria pollutants") are found all over the United States. They are particle pollution (often referred to as particulate matter), ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. These pollutants can harm your health and the environment, and cause property damage. …

EPA calls these pollutants "criteria" air pollutants because it regulates them by developing human health-based and/or environmentally-based criteria (science-based guidelines) for setting permissible levels. The set of limits based on human health is called primary standards. Another set of limits intended to prevent environmental and property damage is called secondary standards. A geographic area with air quality that is cleaner than the primary standard is called an "attainment" area; areas that do not meet the primary standard are called "nonattainment" areas.

"For each of these [criteria] pollutants, EPA tracks two kinds of air pollution trends: air concentrations based on actual measurements of pollutant concentrations in the ambient (outside) air at selected monitoring sites throughout the country, and emissions based on engineering estimates of the total tons of pollutants released into the air each year."

[13] U.S. Code, Title 42, Chapter 85, Subchapter I, Part A, Section 7403: "Research, investigation, training, and other activities." Accessed March 21, 2012 at http://www.law.cornell.edu/uscode/text/42/7403

(a) Research and development program for prevention and control of air pollution

The Administrator shall establish a national research and development program for the prevention and control of air pollution….

In carrying out subsection (a) of this section, the Administrator shall conduct a program of research, testing, and development of methods for sampling, measurement, monitoring, analysis, and modeling of air pollutants.

(a) Air pollutant list; publication and revision by Administrator; issuance of air quality criteria for air pollutants

(1) For the purpose of establishing national primary and secondary ambient air quality standards, the Administrator shall within 30 days after December 31, 1970, publish, and shall from time to time thereafter revise, a list which includes each air pollutant—

(A) emissions of which, in his judgment, cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare;

(B) the presence of which in the ambient air results from numerous or diverse mobile or stationary sources; and

(C) for which air quality criteria had not been issued before December 31, 1970 but for which he plans to issue air quality criteria under this section.

[15] Report: "EPA's Regulation of Coal-Fired Power: Is a 'Train Wreck' Coming?" By James E. McCarthy and Claudia Copeland. Congressional Research Service, August 8, 2011. http://www.fas.org/sgp/crs/misc/R41914.pdf

In essence, NAAQS are standards that define what EPA considers to be clean air. Their importance stems from the long and complicated implementation process that is set in motion by their establishment. Once NAAQS have been set, EPA, using monitoring data and other information submitted by the states to identify areas that exceed the standards and must, therefore, reduce pollutant concentrations to achieve them. State and local governments then have three years to produce State Implementation Plans which outline the measures they will implement to reduce the pollution levels in these "nonattainment" areas. Nonattainment areas are given anywhere from three to 20 years to attain the standards, depending on the pollutant and the severity of the area's pollution problem.

EPA also acts to control many of the NAAQS pollutants wherever they are emitted through national standards for certain products that emit them (particularly mobile sources, such as automobiles) and emission standards for new stationary sources, such as power plants.

In the 1970s, EPA identified six pollutants or groups of pollutants for which it set NAAQS.⁴¹ But that was not the end of the process. When it gave EPA the authority to establish NAAQS, Congress anticipated that the understanding of air pollution's effects on public health and welfare would change with time, and it required that EPA review the standards at five-year intervals and revise them, as appropriate.

Page 6478: "NAAQS decisions can have profound impacts on public health and welfare, and NAAQS decisions should be based on studies that have been rigorously assessed in an integrative manner not only by EPA but also by the statutorily mandated independent advisory committee, as well as the public review that accompanies this process."

Under the Clean Air Act, EPA establishes air quality standards to protect public health and the environment. EPA has set national air quality standards for six common air pollutants. These include:

Each year EPA tracks the levels of these pollutants in the air and how much of each pollutant (or the pollutants that form them) is emitted from various pollution sources. The Agency looks at these numbers year after year to see how the pollutants have changed over time. EPA posts the results of our analyses to this web site.

(A) within 30 days after December 31, 1970, shall publish proposed regulations prescribing a national primary ambient air quality standard and a national secondary ambient air quality standard for each air pollutant for which air quality criteria have been issued prior to such date; and

(B) after a reasonable time for interested persons to submit written comments thereon (but no later than 90 days after the initial publication of such proposed standards) shall by regulation promulgate such proposed national primary and secondary ambient air quality standards with such modifications as he deems appropriate.

(2) With respect to any air pollutant for which air quality criteria are issued after December 31, 1970, the Administrator shall publish, simultaneously with the issuance of such criteria and information, proposed national primary and secondary ambient air quality standards for any such pollutant. The procedure provided for in paragraph (1)(B) of this subsection shall apply to the promulgation of such standards.

(1) National primary ambient air quality standards, prescribed under subsection (a) of this section shall be ambient air quality standards the attainment and maintenance of which in the judgment of the Administrator, based on such criteria and allowing an adequate margin of safety, are requisite to protect the public health. Such primary standards may be revised in the same manner as promulgated.

[19] Report: "EPA's Regulation of Coal-Fired Power: Is a 'Train Wreck' Coming?" By James E. McCarthy and Claudia Copeland. Congressional Research Service, August 8, 2011. http://www.fas.org/sgp/crs/misc/R41914.pdf

Page 17: "In essence, NAAQS are standards that define what EPA considers to be clean air."

(2) Any national secondary ambient air quality standard prescribed under subsection (a) of this section shall specify a level of air quality the attainment and maintenance of which in the judgment of the Administrator, based on such criteria, is requisite to protect the public welfare from any known or anticipated adverse effects associated with the presence of such air pollutant in the ambient air. Such secondary standards may be revised in the same manner as promulgated.

"Primary standards provide public health protection, including protecting the health of "sensitive" populations such as asthmatics, children, and the elderly. Secondary standards provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings."

[23] Report: "Review of National Ambient Air Quality Standards for Carbon Monoxide;

The requirement that primary standards provide an adequate margin of safety was intended to address uncertainties associated with inconclusive scientific and technical information available at the time of standard setting. It was also intended to provide a reasonable degree of protection against hazards that research has not yet identified. See Lead Industries Association v. EPA, 647 F.2d 1130, 1154 (DC Cir. 1980), cert. denied, 449 U.S. 1042 (1980); American Petroleum Institute v. Costle, 665 F.2d 1176, 1186 (DC Cir. 1981), cert. denied, 455 U.S. 1034 (1982); American Farm Bureau Federation v. EPA, 559 F.3d 512, 533 (DC Cir. 2009); Association of Battery Recyclers v. EPA, 604 F.3d 613, 617-18 (DC Cir. 2010). Both kinds of uncertainties are components of the risk associated with pollution at levels below those at which human health effects can be said to occur with reasonable scientific certainty. Thus, in selecting primary standards that provide an adequate margin of safety, the Administrator is seeking not only to prevent pollution levels that have been demonstrated to be harmful but also to prevent lower pollutant levels that may pose an unacceptable risk of harm, even if the risk is not precisely identified as to nature or degree. The CAA [Clean Air Act] does not require the Administrator to establish a primary NAAQS [national ambient air quality standards] at a zero-risk level or at background concentration levels, see Lead Industries v. EPA, 647 F.2d at 1156 n.51, but rather at a level that reduces risk sufficiently so as to protect public health with an adequate margin of safety.

In addressing the requirement for an adequate margin of safety, the EPA considers such factors as the nature and severity of the health effects involved, the size of sensitive population(s) at risk, and the kind and degree of the uncertainties that must be addressed. The selection of any particular approach to providing an adequate margin of safety is a policy choice left specifically to the Administrator's judgment. See Lead Industries Association v. EPA, 647 F.2d at 1161-62; Whitman v. American Trucking Associations, 531 U.S. 457, 495 (2001).

In setting primary and secondary standards that are "requisite'' to protect public health and welfare, respectively, as provided in section 109(b), EPA's task is to establish standards that are neither more nor less stringent than necessary for these purposes. In so doing, EPA may not consider the costs of implementing the standards. See generally, Whitman v. American Trucking Associations, 531 U.S. 457, 465-472, 475-76 (2001). Likewise, "[a]ttainability and technological feasibility are not relevant considerations in the promulgation of national ambient air quality standards.'' American Petroleum Institute v. Costle, 665 F. 2d at 1185.

"2001 The U.S. Supreme Court unanimously upheld the constitutionality of the Clean Air Act as EPA had interpreted it in setting health-protective air quality standards. The Supreme Court also reaffirmed EPA's long-standing interpretation that it must set these standards based solely on public health considerations without consideration of costs."

[25] Book: An Introduction to the U.S. Congress. By Charles B. Cushman Jr. M.E. Sharpe, 2006.

Page 89: "The framers gave the 'advice and consent' powers to the Senate as a check on the power of presidency in two key areas, foreign policy and personnel decisions. … A simple majority of votes cast is enough to confirm a presidential appointment, while treaties require a two-thirds majority for ratification."

[27] Entry: "carbon monoxide." American Heritage Dictionary of Science. Edited by Robert K. Barnhart. Houghton Mifflin, 1986. Page 89.

[28] Calculated with data from: "National Carbon Monoxide Emissions by Source Sector, 2008." EPA, March 18, 2012. http://www.epa.gov/...

NOTE: An Excel file containing the data and calculations is available upon request.

[29] Report: "Quantitative Risk and Exposure Assessment for Carbon Monoxide – Amended." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, July 2010. http://www.epa.gov/...

Page 8-2: "Mobile sources (i.e., gasoline powered vehicles) are the primary contributor to CO emissions, particularly in urban areas due to greater vehicle and roadway densities."

Consistent with the other emissions indicators, the national data are organized into the following source categories: (1) "Stationary sources," which include fuel combustion sources (coal-, gas-, and oil-fired power plants; industrial, commercial, and institutional sources; as well as residential heaters and boilers) and industrial processes (chemical production, petroleum refining, and metals production) categories; (2) "Fires: prescribed burns and wildfires," for insights on contributions from some natural sources; (3) "On-road vehicles," which include cars, trucks, buses, and motorcycles; and (4) "Nonroad vehicles and engines," such as farm and construction equipment, lawnmowers, chainsaws, boats, ships, snowmobiles, aircraft, and others.

[32] Report: "Quantitative Risk and Exposure Assessment for Carbon Monoxide – Amended." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, July 2010. http://www.epa.gov/...

Page 3-20: "Ambient CO concentrations are highest at monitors sited closest to roadways (i.e., microscale and middle scale monitors) and exhibit a diurnal variation linked to the typical commute times of day, with peak concentrations generally observed during early morning and late afternoon during weekdays."

[33] Report: "Quantitative Risk and Exposure Assessment for Carbon Monoxide – Amended." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, July 2010. http://www.epa.gov/...

AT-RISK POPULATIONS The term 'susceptibility' (and the term "at-risk") has been used to recognize populations that have a greater likelihood of experiencing effects related to ambient CO exposure (ISA [Integrated Science Assessment], section 5.7). This increased likelihood of response to CO can potentially result from many factors, including pre-existing medical disorders or disease states, age, gender, lifestyle or increased exposures (ISA, section 5.7). For example, medical disorders that limit the flow of oxygenated blood to the tissues have the potential to make an individual more susceptible to the potential adverse effects of low levels of CO, especially during exercise. Based on the available evidence in the current review, coronary artery disease (CAD), also known as coronary heart disease (CHD) is the "most important susceptibility characteristic for increased risk due to CO exposure" (ISA, p. 2-11). While persons with a normal cardiovascular system can tolerate substantial concentrations of CO if they vasodilate or increase cardiac output in response to the hypoxia produced by CO, those that are unable to vasodilate in response to CO exposure may show evidence of ischemia at low concentrations of COHb (ISA, p. 2-10). There is strong evidence for this in controlled human exposure studies of exercising individuals with CAD, which is supported by results from recent epidemiologic studies reporting associations between short-term CO exposure and increased risk of emergency department visits and hospital admissions for individuals affected with ischemic heart disease (IHD)11 and related outcomes (ISA, section 5.7). This combined evidence, briefly summarized in section 2.5.1 below and described in more detail in the ISA, supports the conclusion that individuals with CAD represent the population most susceptible to increased risk of CO-induced health effects (ISA, sections 5.7.1.1 and 5.7.8).

Coronary artery disease develops when your coronary arteries — the major blood vessels that supply your heart with blood, oxygen and nutrients — become damaged or diseased. Cholesterol-containing deposits (plaques) on your arteries are usually to blame for coronary artery disease.

When plaques build up, they narrow your coronary arteries, causing your heart to receive less blood. Eventually, diminished blood flow may cause chest pain (angina), shortness of breath or other coronary artery disease symptoms. A complete blockage can cause a heart attack.

[35] Report: "Quantitative Risk and Exposure Assessment for Carbon Monoxide – Amended." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, July 2010. http://www.epa.gov/...

The controlled exposure study of principal importance is a large multi-laboratory study designed to evaluate myocardial ischemia, as documented by reductions in time to change in the ST-segment of an electrocardiogram¹⁷ and in time to onset of angina, during a standard treadmill test, at CO exposures targeted to result in mean subject COHb levels of 2% and 4%, as measured by gas chromatographic technique¹⁸ (ISA [Integrated Science Assessment], section 5.2.4, from Allred et al., 1989a, 1989b, 1991). In this study, subjects on three separate occasions underwent an initial graded exercise treadmill test, followed by 50- to 70-minute exposures under resting conditions to average CO concentrations of 0.7 ppm (room air concentration range 0-2 ppm), 117 ppm (range 42-202 ppm) and 253 ppm (range 143-357 ppm). After the 50- to 70-minute exposures, subjects underwent a second graded exercise treadmill test, and the percent change in time to onset of angina and time to ST endpoint between the first and second exercise tests was determined. Relative to clean-air exposure that resulted in a mean COHb level of 0.6% (post-exercise), exposures to CO resulting in post-exercise mean COHb concentrations of 2.0% and 3.9%¹⁹ were shown to decrease the time required to induce ST-segment changes by 5.1% (p=0.01) and 12.1% (p<0.001), respectively. These changes were well correlated with the onset of exercise-induced angina the time to which was shortened by 4.2% (p=0.027) and 7.1% (p=0.002), respectively, for the two CO exposures (ISA, section 5.2.4; Allred et al., 1989a, 1989b, 1991).

¹⁷ The ST-segment is a portion of the electrocardiogram, depression of which is an indication of insufficient oxygen supply to the heart muscle tissue.

Page 2-14: "Although the subjects evaluated in the controlled human exposure studies described above are not necessarily representative of the most sensitive population, the level of disease in these individuals ranged from moderate to severe, with the majority either having a history of myocardial infarction or having ≥ 70% occlusion of one or more of the coronary arteries (ISA, p. 5-43)."

Page 2-16: "Among these studies, the multilaboratory study of Allred et al. (1989a, 1989b, 1991) continues to be the principal study informing our understanding of the effects of CO on individuals with pre-existing CAD [coronary artery disease] at the low end of the range of COHb levels studied (US EPA, 1991, 2000, 2010a)."

Studies have not been designed to evaluate similar effects of exposures to increased CO concentrations eliciting average COHb levels below the 2% target level of Allred et al. (1989a, 1989b, 1991). In addition, these studies do not address the fraction of the population experiencing a specified health effect at various dose levels. These aspects of the evidence contributed to EPA's conclusion that at this time there are insufficient controlled human exposure data to support the development of quantitative dose-response relationships which would be required in order to conduct a quantitative risk assessment for this health endpoint, rather than the benchmark level approach.

An individual's COHb levels reflect their endogenous CO production, as well as CO taken into the body during exposure to ambient and nonambient CO sources. CO uptake into the bloodstream during exposure is influenced by a number of variables including internal levels of CO and COHb, such that net uptake may be lower or negligible in instances where a preceding exposure has been substantially higher than the current one. Thus, the magnitude of the change in COHb level in response to ambient CO exposure may decrease with the presence of concurrent or preceding nonambient CO exposure.

The potential health effect benchmark levels for considering the COHb estimates for the simulated at-risk populations⁸ in this REA [risk assessment analysis] were identified (in section 2.6) based on data from a well-conducted multi-center controlled human exposure study demonstrate cardiovascular effects in subjects with moderate to severe coronary artery disease at study mean COHb levels as low as 2.0-2.4% of which were increased from a baseline mean of 0.6-0.7% as a result of short (~1hour) experimentally controlled increases in CO exposures (study mean of 117 ppm CO). No laboratory study has been specifically designed to evaluate the effect of experimentally increased exposure to CO resulting in an increase in COHb levels to a study mean below 2.0%. However, based on analysis of individual study subject responses at baseline and at the two increased COHb levels, study authors concluded that each increase in COHb produced further changes in the study response metric, without evidence of a measurable threshold effect. There is no established "no adverse effect level" and, thus, there is greater uncertainty concerning the lowest benchmark level identified (i.e., 1.5%).

Page 8-2: "The specific cardiovascular effects occurring at the lowest COHb levels studied in CHD patients are reduced time to exercise-induced angina and other markers of myocardial ischemia, in particular, specific changes to the ST-segment of an electrocardiogram."

[36] Paper: "Short-Term Effects of Carbon Monoxide Exposure on the Exercise Performance of Subjects with Coronary Artery Disease." By Elizabeth N. Allred and others. New England Journal of Medicine, November 23, 1989. Pages 1426-1432. http://www.nejm.org/doi/full/10.1056/NEJM198911233212102

Page 1426: "[T]he differences when the subjects had been exposed to ambient air were then compared with the differences when they were exposed to carbon monoxide levels sufficient to produce 2 percent and 4 percent target carboxyhemoglobin levels."

Page 1428: "Carbon monoxide levels were varied in response to individual rates of uptake, determined during the qualifying visit."

Page 1427: "Blood pressure and a complete electrocardiogram were recorded during each minute of exercise."

Page 1428: "The criteria for stopping the exercise test were as follows: severe fatigue or dyspnea, grade 3 angina, a request by the subject, ST-segment depression of 3 mm, systolic blood pressure ≥240 mm Hg or diastolic blood pressure ≥130 mm Hg, a drop of 20 mm in the systolic blood pressure, or important arrhythmias."

Page 1430: "The results of this study provide objective evidence that increasing the mean carboxyhemoglobin level from 0.6 percent to 2.0 percent worsens the ischemic response to mild graded exercise."

"Carbon Monoxide … primary … 8-hour [=] 9 ppm … 1-hour [=] 35 ppm … Not to be exceeded more than once per year"

[38] Report: "Quantitative Risk and Exposure Assessment for Carbon Monoxide – Amended." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, July 2010. http://www.epa.gov/...

The current NAAQS [national ambient air quality standards] for CO includes two primary standards to provide protection for exposures to carbon monoxide. In 1994, EPA retained the primary standards at 9 parts per million (ppm), 8-hour average and 35 ppm, 1-hour average, neither to be exceeded more than once per year (59 FR 38906). These standards were based primarily on the clinical evidence relating carboxyhemoglobin (COHb) levels to various adverse health endpoints and exposure modeling relating CO exposures to COHb levels.

[39] Calculated with the dataset: "CO Air Quality, 1980-2010, National Trend based on 104 Sites (Annual 2nd Maximum 8-hour Average)." EPA, March 26, 2012. http://www.epa.gov/airtrends/carbon.html

NOTE: An Excel file containing the data and calculations is available upon request.

"Everywhere in the country has air quality that meets the current CO standards. Most sites have measured concentrations below the national standards since the early 1990s, since which time, improvements in motor vehicle emissions controls have contributed to significant reductions in ambient concentrations."

"Number of People Living in Counties with Air Quality Concentrations Above the Level of the NAAQS [national ambient air quality standard] in 2010 … CO (8-hour) [=] 0.0"

[43] Report: "Quantitative Risk and Exposure Assessment for Carbon Monoxide – Amended." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, July 2010. http://www.epa.gov/...

Page 8-2: "Recent (2005-2007) ambient CO concentrations across the US are lower than those reported in the previous CO NAAQS review and are also well below the current CO NAAQS levels. Further, a large proportion of the reported concentrations are below the conventional instrument lower detectable limit of 1 ppm."

Ozone has the same chemical structure whether it occurs miles above the earth or at ground-level and can be "good" or "bad," depending on its location in the atmosphere.

In the earth's lower atmosphere, ground-level ozone is considered "bad." Motor vehicle exhaust and industrial emissions, gasoline vapors, and chemical solvents as well as natural sources emit NOx and VOC that help form ozone. Ground-level ozone is the primary constituent of smog. …

"Good" ozone occurs naturally in the stratosphere approximately 10 to 30 miles above the earth's surface and forms a layer that protects life on earth from the sun's harmful rays.

"Ozone (O3) is a gas composed of three oxygen atoms. It is not usually emitted directly into the air, but at ground-level is created by a chemical reaction between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight."

[47] Dataset: "National Nitrogen Oxides Emissions by Source Sector, 2008." EPA, March 17, 2012. http://www.epa.gov/...

[49] Dataset: "National Volatile Organic Compounds Emissions by Source Sector, 2008." EPA, March 17, 2012. http://www.epa.gov/...

Ozone in the air we breathe can harm our health—typically on hot, sunny days when ozone can reach unhealthy levels. Even relatively low levels of ozone can cause health effects. People with lung disease, children, older adults, and people who are active outdoors may be particularly sensitive to ozone.

Children are at greatest risk from exposure to ozone because their lungs are still developing and they are more likely to be active outdoors when ozone levels are high, which increases their exposure. Children are also more likely than adults to have asthma.

[52] Report: "Air Quality Criteria for Ozone and Related Photochemical Oxidants (Volume I of III)." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, February 28, 2006. http://oaspub.epa.gov/eims/eimscomm.getfile?p_download_id=456384

Children, adolescents, and young adults (<18 yrs of age) appear, on average, to have nearly equivalent spirometric [vital lung capacity] responses to O3, but have greater responses than middle-aged and older adults when exposed to comparable O3 doses…. Symptomatic responses to O3 exposure, however, appear to increase with age until early adulthood and then gradually decrease with increasing age…. In contrast to young adults, the diminished symptomatic responses in children and the elderly may put the latter groups at increased risk for continued O3 exposure.

There is a tendency for slightly increased spirometric responses in mild asthmatics and allergic rhinitics relative to healthy young adults. Spirometric responses in asthmatics appear to be affected by baseline lung function, i.e., responses increase with disease severity. With repeated daily O3 exposures, spirometric responses of asthmatics become attenuated; however, airway responsiveness becomes increased in subjects with preexisting allergic airway disease (with or without asthma). Possibly due to patient age, O3 exposure does not appear to cause significant pulmonary function impairment or evidence of cardiovascular strain in patients with cardiovascular disease or chronic obstructive pulmonary disease relative to healthy subjects.

"Ozone is particularly likely to reach unhealthy levels on hot sunny days in urban environments."

Sunlight and hot weather cause ground-level ozone to form in harmful concentrations in the air. As a result, it is known as a summertime air pollutant. Many urban areas tend to have high levels of "bad" ozone, but even rural areas are also subject to increased ozone levels because wind carries ozone and pollutants that form it hundreds of miles away from their original sources.

[55] Report: "Air Quality Criteria for Ozone and Related Photochemical Oxidants (Volume I of III)." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, February 28, 2006. http://oaspub.epa.gov/eims/eimscomm.getfile?p_download_id=456384

Studies on the effect of elevation on O3 concentrations found that concentrations increased with increasing elevation…. Since O3 monitors are frequently located on rooftops in urban settings, the concentrations measured there may overestimate the exposure to individuals outdoors in streets and parks, locations where people exercise and their maximum O3 exposure is more likely to occur. …

There is no clear consensus among exposure analysts as to how well stationary monitor measurements of ambient O3 concentrations represent a surrogate for personal O3 exposure. …

The use of central ambient monitors to estimate personal exposure has a greater potential to introduce bias since most people spend the majority of their time indoors, where O3 levels tend to be much lower than outdoor ambient levels. …

Several studies have examined relationships between measured ambient O3 concentrations from fixed monitoring sites and personal O3 exposure…. Two studies by Sarnat et al. (2001, 2005) examined relationships between individual variations in personal exposure and ambient O3 concentrations. … In the Boston study, the regression coefficients indicated that ambient O3 concentrations were predictive of personal O3 exposures; however, ambient O3 levels overestimated personal exposures 3- to 4-fold in the summer and 25-fold in the winter.

Page 7-6: "In several studies focused on evaluating exposure to O3, measurements were made in a variety of indoor environments, including homes (Lee et al., 2004), schools (Linn et al., 1996), and the workplace (Liu et al., 1995). Indoor O3 concentrations were, in general, approximately one-tenth of the outdoor concentrations in these studies."

Use of ambient monitors to determine exposure will generally overestimate true personal O3 exposure (because their use implies that subjects are outdoors 100% of their time and not in close proximity to sources that reduce O3 levels such as NO emissions from mobile sources); thus, generally, their use can result in effect estimates that are biased toward the null if the error is not of a fixed amount.

Existing epidemiologic models may not fully take into consideration all the biologically relevant exposure history or reflect the complexities of all the underlying biological processes. Using ambient concentrations to determine exposure generally overestimates true personal O3 exposures (by approximately 2- to 4- fold in the various studies described in Section 3.9), resulting in biased descriptions of underlying concentration-response relationships (i.e., in attenuated risk estimates). The implication is that the effects being estimated occur at fairly low exposures and the potency of O3 is greater than these effect estimates indicate. As very few studies evaluating O3 health effects with personal O3 exposure measurements exist in the literature, effect estimates determined from ambient O3 concentrations must be evaluated and used with caution to assess the health risks of O3.

The ultimate goal of the O3 NAAQS is to set a standard for the ambient level, not personal exposure level, of O3. Until more data on personal O3 exposure become available, the use of routinely monitored ambient O3 concentrations as a surrogate for personal exposures is not generally expected to change the principal conclusions from O3 epidemiologic studies. Therefore, population health risk estimates derived using ambient O3 levels from currently available observational studies (with appropriate caveats taking into account personal exposure considerations) remain useful.

"Ozone … primary and secondary … 8-hour [=] 0.075 ppm … Annual fourth-highest daily maximum 8-hr concentration, averaged over 3 years"

[57] Code of Federal Regulations, Title 40, Part 50, Appendix I: "Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone." U.S. Government Printing Office, July 1, 2011. http://www.gpo.gov/...

2.1.2 Daily maximum 8-hour average concentrations. (a) There are 24 possible running 8-hour average ozone concentrations for each calendar day during the ozone monitoring season. (Ozone monitoring seasons vary by geographic location as designated in part 58, appendix D to this chapter.) The daily maximum 8-hour concentration for a given calendar day is the highest of the 24 possible 8-hour average concentrations computed for that day. This process is repeated, yielding a daily maximum 8-hour average ozone concentration for each calendar day with ambient ozone monitoring data. Because the 8- hour averages are recorded in the start hour, the daily maximum 8-hour concentrations from two consecutive days may have some hourly concentrations in common. Generally, overlapping daily maximum 8-hour averages are not likely, except in those nonurban monitoring locations with less pronounced diurnal variation in hourly concentrations.

2.2 Primary and Secondary Standard-related Summary Statistic. The standard-related summary statistic is the annual fourth-highest daily maximum 8-hour ozone concentration, expressed in parts per million, averaged over three years. The 3-year average shall be computed using the three most recent, consecutive calendar years of monitoring data meeting the data completeness requirements described in this appendix. The computed 3- year average of the annual fourth-highest daily maximum 8-hour average ozone concentrations shall be expressed to three decimal places (the remaining digits to the right are truncated.)

[58] Calculated with the dataset: "Ozone Air Quality, 1980-2010, National Trend based on 247 Sites (Annual 4th Maximum 8-Hour Average)." EPA, January 06, 2012. http://www.epa.gov/airtrends/ozone.html

NOTE: An Excel file containing the data and calculations is available upon request.

NOTE: The EPA's ozone standards for earlier years are not shown in the graph because they are based on parameters that are not graphically comparable to the current standard.

"Number of People Living in Counties with Air Quality Concentrations Above the Level of the NAAQS [national ambient air quality standard] in 2010 … Ozone (8-hour) [=] 108.0"

CALCULATION: 108.0 million people living in counties with air quality above NAAQS / 309.3 million population = 34.9%

[61] Report: "National Ambient Air Quality Standards for Lead; Final Rule (Part II)." Federal Register (Vol. 73, No. 219), EPA, November 12, 2008. http://www.epa.gov/...

(1) Lead is emitted into the air from many sources encompassing a wide variety of stationary and mobile source types. Lead emitted to the air is predominantly in particulate form, with the particles occurring in various sizes. Once emitted, the particles can be transported long or short distances depending on their size, which influences the amount of time spent in aerosol phase. In general, larger particles tend to deposit more quickly, within shorter distances from emissions points, while smaller particles will remain in aerosol phase and travel longer distances before depositing. …

(2) Once deposited out of the air, Pb can subsequently be resuspended into the ambient air and, because of the persistence of Pb, Pb emissions contribute to media concentrations for some years into the future.

(3) Exposure to Pb emitted into the ambient air (air-related Pb) can occur directly by inhalation, or indirectly by ingestion of Pb-contaminated food, water or other materials including dust and soil.¹⁰ This occurs as Pb emitted into the ambient air is distributed to other environmental media and can contribute to human exposures via indoor and outdoor dusts, outdoor soil, food and drinking water, as well as inhalation of air.

"Lead and its compounds are toxic and are retained by the body, accumulating over a long period of time—a phenomenon known as cumulative poisoning—until a lethal quantity is reached. In children the accumulation of lead may result in cognitive deficits; in adults it may produce progressive renal disease."

• Neurobehavioral effects of Pb-exposure early in development (during fetal, neonatal, and later postnatal periods) in young infants and children (#7 years old) have been observed with remarkable consistency across numerous studies involving varying study designs, different developmental assessment protocols, and diverse populations. Negative Pb impacts on neurocognitive ability and other neurobehavioral outcomes are robust in most recent studies even after adjustment for numerous potentially confounding factors (including quality of care giving, parental intelligence, and socioeconomic status). These effects generally appear to persist into adolescence and young adulthood. …

• In the limited literature examining the effects of environmental Pb exposure on adults, mixed evidence exists regarding associations between Pb and neurocognitive performance. No associations were observed between cognitive performance and blood Pb levels; however, significant associations were observed in relation to bone Pb concentrations, suggesting that long-term cumulative Pb exposure may contribute to neurocognitive deficits in adults.

Page E-10: "Epidemiologic studies have consistently demonstrated associations between Pb exposure and enhanced risk of deleterious cardiovascular outcomes, including increased blood pressure and incidence of hypertension."

Page E-11: "In the general population, both circulating and cumulative Pb was found to be associated with longitudinal decline in renal function. Effects on creatine clearance have been reported in human adult hypertensives to be associated with general population mean blood-Pb levels of only 4.2 μg/dL. The public health significance of such effects is not clear, however, in view of more serious signs of kidney dysfunction being seen in occupationally exposed workers only at much higher blood-Pb levels (>30-40 μg/dL)."

[64] Dataset: "National Lead Emissions by Source Sector, 2008." EPA, March 18, 2012. http://www.epa.gov/...

Historically, mobile sources were a major source of Pb emissions, due to the use of leaded gasoline. The United States initiated the phasedown of gasoline Pb additives in the late 1970s and intensified the phase-out of Pb additives in 1990. Accordingly, airborne Pb concentrations have fallen dramatically nationwide, decreasing an average of 94% between 1983 and 2002. This is considered one of the great public and environmental health successes. Remaining mobile source-related emissions of Pb include brake wear, resuspended road dust, and emissions from vehicles that continue to use leaded gasoline (e.g., some types of aircraft and race cars).

For most of the past 50 to 60 years, the primary use of Pb was as additives for gasoline. Leaded gasoline use peaked in the 1970s, and worldwide consumption has declined since (Nriagu, 1990). The largest source of air-Pb emissions was leaded gasoline throughout the 1970s and 1980s. In 1980, on-road vehicles were responsible for ~80% of air-Pb emissions, whereas in 2002, on-road vehicles contributed less than half of a percent (U.S. Environmental Protection Agency, 2003). In every case where the U.S. Pb NAAQS has been exceeded since 2002, stationary point sources were responsible (www.epa.gov/air/oaqps/greenbk/inte.html).

Measurements made in Riverside, CA show diurnal trends (Singh et al., 2002). Lead concentrations are high in the morning (6 to 10 a.m.) and the late afternoon (4 to 8 p.m.). This is most probably indicative of heavy traffic, despite the use of unleaded gasoline, a depressed atmospheric mixing height in the morning, and advection from Los Angeles traffic. Lead concentrations in Riverside are significantly lower during midday (10 a.m. to 4 p.m.) and night (8 p.m. to 6 a.m.).

The highest air, soil, and road dust concentrations are found near major Pb sources, such as smelters, mines, and heavily trafficked roadways. While airborne Pb concentrations have declined dramatically with the phase out of leaded gasoline, soil concentrations have remained relatively constant, reflecting the generally long retention time of Pb in soil. Soil-Pb concentrations decrease both with depth and distance from roadways and sources such as smelters or mines. In another study of 831 homes in the United States, 7% of housing units were found to have soil-Pb levels exceeding 1200 ppm, the U.S.EPA/HUD standard for soil-Pb concentration outside of play areas (Jacobs et al., 2002).

[69] Report: "National Ambient Air Quality Standards for Lead; Final Rule (Part II)." Federal Register (Vol. 73, No. 219), EPA, November 12, 2008. http://www.epa.gov/...

Page 66983: "With regard to the sensitive population, while the sensitivity of the elderly and other particular subgroups is recognized, as at the time the current standard was set, young children continue to be recognized as a key sensitive population for Pb exposures."

Page 6-1: "Children are particularly at risk due to sources of exposure, mode of entry, rate of absorption and retention, and partitioning of Pb in soft and hard tissues. The greater sensitivity of children to Pb toxicity, their inability to recognize symptoms, and their dependence on parents and healthcare professionals make them an especially vulnerable population requiring special consideration in developing criteria and standards for Pb."

Lead effects on neurobehavior in children have been observed with remarkable consistency across numerous studies of various designs, populations, and developmental assessment protocols. The negative impacts of Pb on neurocognitive ability and other neurobehavioral outcomes persist in most recent studies even after adjustment for numerous confounding factors, including social class, quality of caregiving, and parental intelligence. These effects appear to persist into adolescence and young adulthood. Collectively, the prospective cohort and cross-sectional studies offer evidence that exposure to Pb affects the intellectual attainment of preschool and school age children at blood Pb levels <10 μg/dL (most clearly in the 5 to 10 μg/dL range, but, less definitively, possibly lower). Epidemiologic studies have demonstrated that Pb may also be associated with increased risk for antisocial and delinquent behavior, which may be a consequence of attention problems and academic underachievement among children who may have suffered higher exposures to Pb during their formative years.

[71] Report: "National Ambient Air Quality Standards for Lead; Final Rule (Part II)." Federal Register (Vol. 73, No. 219), EPA, November 12, 2008. http://www.epa.gov/...

[T]he Administrator [of the EPA] proposed to conclude that an air-related population mean IQ loss within the range of 1 to 2 points could be significant from a public health perspective, and that a standard level should be selected to provide protection from air-related population mean IQ loss in excess of this range. …

The proposal noted that there is no bright line clearly directing the choice of level within this reasonable range, and therefore the choice of what is appropriate, considering the strengths and limitations of the evidence, and the appropriate inferences to be drawn from the evidence and the exposure and risk assessments, is a public health policy judgment.

In addition, the Administrator noted that for standard levels below 0.10 μg/ m³, the estimated degree of impact on population mean IQ loss from air-related Pb would generally be somewhat to well below the proposed range of 1 to 2 points air-related population mean IQ loss regardless of which set of C–R [concentration-response] functions or which air-to-blood ratio within the range of ratios considered are used. The Administrator proposed to conclude that the degree of public health protection that standards below 0.10 μg/m³ would likely afford would be greater than what is requisite to protect public health with an adequate margin of safety.

Having reached these proposed decisions based on the interpretation of the evidence, the evidence-based frameworks, the exposure/risk assessment, and the public health policy judgments described above, the Administrator recognized that other interpretations, frameworks, assessments, and judgments are possible.

[I]t is important to recognize that the air-related IQ loss framework provides estimates for the mean of a subset of the population. It is an estimate for a subset of children that are assumed to be exposed to the level of the standard. The framework in effect focuses on the sensitive subpopulation that is the group of children living near sources and more likely to be exposed at the level of the standard. The evidence-based framework estimates a mean air-related IQ loss for this subpopulation of children; it does not estimate a mean for all U.S. children.

EPA is unable to quantify the percentile of the U.S. population of children that corresponds to the mean of this sensitive subpopulation. Nor is EPA confident in its ability to develop quantified estimates of air-related IQ loss for higher percentiles than the mean of this subpopulation. EPA expects that the mean of this subpopulation represents a high, but not quantifiable, percentile of the U.S. population of children. As a result, EPA expects that a standard based on consideration of this framework would provide the same or greater protection from estimated air-related IQ loss for a high, albeit unquantifiable, percentage of the entire population of U.S. children.

"Lead … primary and secondary … Rolling 3-month average [=] 0.15 μg/m³ … Not to be exceeded"

[73] Calculated with the dataset: "Lead Air Quality, 1980-2010, National Trend based on 31 Sites (Annual Maximum 3-Month Average)." EPA, January 06, 2012. http://www.epa.gov/airtrends/carbon.html

NOTE: An Excel file containing the data and calculations is available upon request.

NOTE: From 1978-2008, the averaging time was over each calendar quarter. In 2008, the EPA changed this to a rolling 3-month period.

"Number of People Living in Counties with Air Quality Concentrations Above the Level of the NAAQS [national ambient air quality standard] in 2010 … Lead (3-month) [=] 20.2"

CALCULATION: 20.2 million people living in counties with air quality above NAAQS / 309.3 million population = 6.5%

Nitrogen dioxide (NO2) is one of a group of highly reactive gasses known as "oxides of nitrogen," or "nitrogen oxides (NOx)." Other nitrogen oxides include nitrous acid and nitric acid. While EPA's National Ambient Air Quality Standard covers this entire group of NOx, NO2 is the component of greatest interest and the indicator for the larger group of nitrogen oxides. NO2 forms quickly from emissions from cars, trucks and buses, power plants, and off-road equipment. In addition to contributing to the formation of ground-level ozone, and fine particle pollution, NO2 is linked with a number of adverse effects on the respiratory system.

In the last review of the NO2 NAAQS [National Ambient Air Quality Standards], the 1993 NOX Air Quality Criteria Document (1993 AQCD) (EPA, 1993) concluded that there were two key health effects of greatest concern at ambient or near-ambient concentrations of NO2 (ISA, section 5.3.1). The first was increased airway responsiveness in asthmatic individuals after short-term exposures. The second was increased respiratory illness among children associated with longer-term exposures to NO2. Evidence also was found for increased risk of emphysema, but this appeared to be of major concern only with exposures to NO2 at levels much higher than then current ambient levels (ISA, section 5.3.1).

As summarized below and discussed more fully in section II.B of the proposal notice, evidence published since the last review generally has confirmed and extended the conclusions articulated in the 1993 AQCD….

Overall, the epidemiologic evidence for respiratory effects has been characterized in the ISA [Integrated Science Assessment] as consistent, in that associations are reported in studies conducted in numerous locations with a variety of methodological approaches, and coherent, in that the studies report associations with respiratory health outcomes that are logically linked together. In addition, a number of these associations are statistically significant, particularly the more precise effect estimates (ISA, section 5.3.2.1). These epidemiologic studies are supported by evidence from toxicological and controlled human exposure studies, particularly those that evaluated airway hyperresponsiveness in asthmatic individuals (ISA, section 5.4). The ISA concluded that together, the epidemiologic and experimental data sets form a plausible, consistent, and coherent description of a relationship between NO2 exposures and an array of adverse respiratory health effects that range from the onset of respiratory symptoms to hospital admissions.

Page 6482: "As noted above in section II.A, the only health effect category for which the evidence was judged in the ISA [Integrated Science Assessment] to be sufficient to infer either a causal or a likely causal relationship is respiratory morbidity following short-term NO2 exposure."

[78] Dataset: "National Nitrogen Oxides Emissions by Source Sector, 2008." EPA, March 18, 2012. http://www.epa.gov/...

While driving, personal exposure [NO2] concentrations in the cabin of a vehicle could be substantially higher than ambient concentrations measured nearby…. For example, estimates presented in the REA [Risk and Exposure Assessment] suggest that on/near roadway NO2 concentrations could be approximately 80% (REA, section 7.3.2) higher on average across locations than concentrations away from roadways and that roadway-associated environments could be responsible for the majority of 1-hour peak NO2 exposures (REA, Figures 8–17 and 8–18). Because monitors in the current network are not sited to measure peak roadway-associated NO2 concentrations, individuals who spend time on and/or near major roadways could experience NO2 concentrations that are considerably higher than indicated by monitors in the current area-wide NO2 monitoring network.

Research suggests that the concentrations of on-road mobile source pollutants such as NOX, carbon monoxide (CO), directly emitted air toxics, and certain size distributions of particulate matter (PM), such as ultrafine PM, typically display peak concentrations on or immediately adjacent to roads (ISA [Integrated Science Assessment], section 2.5). This situation typically produces a gradient in pollutant concentrations, with concentrations decreasing with increasing distance from the road, and concentrations generally decreasing to near area-wide ambient levels, or typical upwind urban background levels, within a few hundred meters downwind. While such a concentration gradient is present on almost all roads, the characteristics of the gradient, including the distance from the road that a mobile source pollutant signature can be differentiated from background concentrations, are heavily dependent on factors such as traffic volumes, local topography, roadside features, meteorology, and photochemical reactivity conditions….

… As a result, we have identified a range of concentration gradients in the technical literature which indicate that, on average, peak NO2 concentrations on or immediately adjacent to roads may typically be between 30 and 100 percent greater than concentrations monitored in the same area but farther away from the road…. This range of concentration gradients has implications for revising the NO2 primary standard and for the NO2 monitoring network (discussed in sections II.F.4 and III).

Based on data from the 2003 American Housing Survey, approximately 36 million individuals live within 300 feet (∼90 meters) of a four-lane highway, railroad, or airport (ISA, section 4.4).7 Furthermore, in California, 2.3% of schools, with a total enrollment of more than 150,000 students were located within approximately 500 feet of high-traffic roads, with a higher proportion of non-white and economically disadvantaged students attending those schools (ISA, section 4.4).

In the last review of the NO2 NAAQS [National Ambient Air Quality Standards], the 1993 NOX Air Quality Criteria Document (1993 AQCD) (EPA, 1993) concluded that there were two key health effects of greatest concern at ambient or near-ambient concentrations of NO2 (ISA [Integrated Science Assessment], section 5.3.1). The first was increased airway responsiveness in asthmatic individuals after short-term exposures. The second was increased respiratory illness among children associated with longer-term exposures to NO2. Evidence also was found for increased risk of emphysema, but this appeared to be of major concern only with exposures to NO2 at levels much higher than then current ambient levels (ISA, section 5.3.1).

Overall, the epidemiologic evidence for respiratory effects has been characterized in the ISA as consistent, in that associations are reported in studies conducted in numerous locations with a variety of methodological approaches, and coherent, in that the studies report associations with respiratory health outcomes that are logically linked together. In addition, a number of these associations are statistically significant, particularly the more precise effect estimates (ISA, section 5.3.2.1). These epidemiologic studies are supported by evidence from toxicological and controlled human exposure studies, particularly those that evaluated airway hyperresponsiveness in asthmatic individuals (ISA, section 5.4). The ISA concluded that together, the epidemiologic and experimental data sets form a plausible, consistent, and coherent description of a relationship between NO2 exposures and an array of adverse respiratory health effects that range from the onset of respiratory symptoms to hospital admissions.

In the United States, approximately 10% of adults and 13% of children (approximately 22.2 million people in 2005) have been diagnosed with asthma, and 6% of adults have been diagnosed with COPD [chronic obstructive pulmonary disease] (ISA, section 4.4). The prevalence and severity of asthma is higher among certain ethnic or racial groups such as Puerto Ricans, American Indians, Alaskan Natives, and African Americans (ISA, section 4.4). A higher prevalence of asthma among persons of lower SES [socioeconomic status] and an excess burden of asthma hospitalizations and mortality in minority and inner-city communities have been observed (ISA, section 4.4). …

As noted above in section II.A, the only health effect category for which the evidence was judged in the ISA [Integrated Science Assessment] to be sufficient to infer either a causal or a likely causal relationship is respiratory morbidity following short-term NO2 exposure."

"Nitrogen Dioxide … primary and secondary … Annual [=] 53 ppb … Annual Mean"

[83] Calculated with the dataset: "Nitrogen Dioxide Air Quality, 1980-2010, National Trend based on 81 Sites (Annual Arithmetic Average)." EPA, January 06, 2012. http://www.epa.gov/airtrends/carbon.html

NOTE: An Excel file containing the data and calculations is available upon request.

[84] Web page: "History of the National Ambient Air Quality Standards for Oxides of Nitrogen

"Number of People Living in Counties with Air Quality Concentrations Above the Level of the NAAQS [national ambient air quality standard] in 2010 … NO2 (annual) [=] 0.0"

Specifically, EPA is supplementing the existing annual standard for NO2 of 53 parts per billion (ppb) by establishing a new short-term standard based on the 3- year average of the 98th percentile of the yearly distribution of 1-hour daily maximum concentrations. EPA is setting the level of this new standard at 100 ppb. EPA is making changes in data handling conventions for NO2 by adding provisions for this new 1-hour primary standard. EPA is also establishing requirements for an NO2 monitoring network. These new provisions require monitors at locations where maximum NO2 concentrations are expected to occur, including within 50 meters of major roadways, as well as monitors sited to measure the area-wide NO2 concentrations that occur more broadly across communities. EPA is making conforming changes to the air quality index (AQI).

[88] NOTE: Although this citation (below) refers to sulfur dioxide, as shown in the footnote above, the particulars regarding implementation time are similar for nitrogen dioxide. New monitors will need to be installed, and three years of data must be collected to determine which counties meet the new standard.

Report: "EPA's Regulation of Coal-Fired Power: Is a 'Train Wreck' Coming?" By James E. McCarthy and Claudia Copeland. Congressional Research Service, August 8, 2011. http://www.fas.org/sgp/crs/misc/R41914.pdf

On June 22, 2010, EPA revised the NAAQS [National Ambient Air Quality Standard] for SO2, focusing on short-term (1-hour) exposures. …

The timing and extent of any additional controls is uncertain, however, for several reasons. First, the monitoring network needed to determine attainment status is incomplete and is not primarily configured to monitor locations of maximum short-term SO2 concentrations. … Since three years of data must be collected after a site's startup to determine attainment status, it may be as late as 2016 before some areas will have sufficient data to be classified. Even if the areas can be designated sooner based on modeling data, it would be at least 2015 before State Implementation Plans with specific control measures would be due, and actual compliance with control requirements would occur several years later.

"Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.

The size of particles is directly linked to their potential for causing health problems. EPA is concerned about particles that are 10 micrometers in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. EPA groups particle pollution into two categories:

• "Inhalable coarse particles," such as those found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter.

• "Fine particles," such as those found in smoke and haze, are 2.5 micrometers in diameter and smaller. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air.

Particulate matter is the generic term for a broad class of chemically and physically diverse substances that exist as discrete particles (liquid droplets or solids) over a wide range of sizes. Particles originate from a variety of anthropogenic stationary and mobile sources as well as from natural sources. Particles may be emitted directly or formed in the atmosphere by transformations of gaseous emissions such as sulfur oxides (SOX), nitrogen oxides (NOX), and volatile organic compounds (VOC). The chemical and physical properties of PM vary greatly with time, region, meteorology, and source category, thus complicating the assessment of health and welfare effects.

For morbidity, the Criteria Document found that new studies of a cohort of children in Southern California have built upon earlier limited evidence to provide fairly strong evidence that long-term exposure to fine particles is associated with development of chronic respiratory disease and reduced lung function growth (EPA, 2004a, pp. 9–33 to 9–34). In addition to strengthening the evidence of association, the new extended ACS mortality study (Pope et al., 2002) observed statistically significant associations with cardiorespiratory mortality (including lung cancer mortality) across a range of long-term mean PM2.5 concentrations that was lower than was reported in the original ACS study available in the last review. …

In reviewing this information, the Staff Paper recognized that important limitations and uncertainties associated with this expanded body of evidence for PM2.5 and other indicators or components of fine particles need to be carefully considered in determining the weight to be placed on the body of studies available in this review. For example, the Criteria Document noted that although PM-effects associations continue to be observed across most new studies, the newer findings do not fully resolve the extent to which the associations are properly attributed to PM acting alone or in combination with other gaseous co-pollutants or to the gaseous co-pollutants themselves. The Criteria Document concluded, however, that overall the newly available epidemiologic evidence, especially for the more numerous short-term exposure studies, substantiates that associations for various PM indicators with mortality and morbidity are robust to confounding by co-pollutants (EPA, 2004a, p. 9–37).

"How Big is Particle Pollution? .. Human Hair ~ 70 μm average diameter … PM2.5 = <2.5 μm in diameter … PM10 <10 μm in diameter"

More specifically, the PM that is the subject of the air quality criteria and standards reviews includes both fine particles and thoracic coarse particles, which are considered as separate subclasses of PM pollution based in part on long-established information on differences in sources, properties, and atmospheric behavior between fine and coarse particles…. Fine particles are produced chiefly by combustion processes and by atmospheric reactions of various gaseous pollutants, whereas thoracic coarse particles are generally emitted directly as particles as a result of mechanical processes that crush or grind larger particles or the resuspension of dusts. Sources of fine particles include, for example, motor vehicles, power generation, combustion sources at industrial facilities, and residential fuel burning. …

The last review of PM air quality criteria and standards was completed in July 1997 with notice of a final decision to revise the existing standards…. In that decision, EPA revised the PM NAAQS in several respects. While EPA determined that the PM NAAQS [National Ambient Air Quality Standards] should continue to focus on particles less than or equal to 10 μm in diameter (PM10), EPA also determined that the fine and coarse fractions of PM10 should be considered separately. The EPA added new standards, using PM2.5 as the indicator for fine particles (with PM2.5 referring to particles with a nominal aerodynamic diameter less than or equal to 2.5 μm), and using PM10 as the indicator for purposes of regulating the coarse fraction of PM10 (referred to as thoracic coarse particles or coarse-fraction particles; generally including particles with a nominal aerodynamic diameter greater than 2.5 μm and less than or equal to 10 μm, or PM10–2.5).

Page 61149: "Programs aimed at reducing direct emissions of particles have played an important role in reducing PM10 concentrations, particularly in western areas. Some examples of PM10 controls include paving unpaved roads and using best management practices for agricultural sources of resuspended soil."

During a changeout campaign, consumers receive financial incentives (rebates) to replace older appliances with either non-wood-burning equipment (for example, vented gas stoves), pellet stoves, or EPA certified wood stoves. Approximately 10 million wood stoves are currently in use in the United States, and 70 to 80 percent of them are older, inefficient, conventional stoves that pollute. Because EPA certified wood stoves emit approximately 70 percent less pollution than older, conventional wood stoves, a successful changeout campaign will reduce local particulate emissions.

[95] Draft Report: "Lists of Potential Control Measures for PM2.5 and Precursors." EPA, undated. http://www.epa.gov/...

These informational documents are intended to provide a broad, though not comprehensive, listing of potential emissions reduction measures for direct PM2.5 and precursors. The purpose is primarily to assist states in identifying and evaluating potential measures as States develop plans for attaining the PM2.5 NAAQS.

Before examining control measures, an important step for States is to identify the nature of the PM2.5 problem in their areas and the sources contributing to that problem. The severity, nature and sources of the PM2.5 problem vary in each nonattainment area, so the measures that are effective and cost-effective will also vary by area. Similarly, the geographic area in which measures are effectively applied will vary depending on the extent to which pollution sources outside the nonattainment area contribute to the area's PM2.5 problem. …

All industrial and commercial sources currently controlling PM with cyclones or multicylones … Upgrade to high-efficiency collection device to collect fine fraction of PM

Stationary diesel engines including generators and other prime service engines … Diesel particulate filter

The nature of the effects that have been reported to be associated with fine particle exposures including premature mortality, aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions and emergency department visits), changes in lung function and increased respiratory symptoms, as well as new evidence for more subtle indicators of cardiovascular health. …

Sensitive or vulnerable subpopulations that appear to be at greater risk to such effects, including individuals with pre-existing heart and lung diseases, older adults, and children. …

The expanded and updated assessment conducted in this review included estimates of risks of mortality (total non-accidental, cardiovascular, and respiratory), morbidity (hospital admissions for cardiovascular and respiratory causes), and respiratory symptoms (not requiring hospitalization) associated with recent short-term (daily) ambient PM2.5 levels and risks of total, cardiopulmonary, and lung cancer mortality associated with long-term exposure to PM2.5 in a number of example urban areas. …

The EPA recognized that there were many sources of uncertainty and variability inherent in the inputs to this assessment and that there was a high degree of uncertainty in the resulting PM2.5 risk estimates. Such uncertainties generally relate to a lack of clear understanding of a number of important factors, including, for example, the shape of concentration-response functions, particularly when, as here, effect thresholds can neither be discerned nor determined not to exist; issues related to selection of appropriate statistical models for the analysis of the epidemiologic data; the role of potentially confounding and modifying factors in the concentration-response relationships; issues related to simulating how PM2.5 air quality distributions will likely change in any given area upon attaining a particular standard, since strategies to reduce emissions are not yet defined; and whether there would be differential reductions in the many components within PM2.5 and, if so, whether this would result in differential reductions in risk. While some of these uncertainties were addressed quantitatively in the form of estimated confidence ranges around central risk estimates, other uncertainties and the variability in key inputs were not reflected in these confidence ranges, but rather were addressed through separate sensitivity analyses or characterized qualitatively.

[97] Dataset: "National PM10 Emissions by Source Sector, 2008." EPA, March 18, 2012. http://www.epa.gov/...

"Particle Pollution … PM10 primary and secondary … 24-hour [=] 150 μg/m³ … Not to be exceeded more than once per year on average over 3 years"

[100] Calculated with the dataset: "PM10 Air Quality, 1990-2010, National Trend based on 279 Sites (Annual 2nd Maximum 24-Hour Average)." EPA, January 06, 2012. http://www.epa.gov/airtrends/pm.html

NOTE: An Excel file containing the data and calculations is available upon request.

"Number of People Living in Counties with Air Quality Concentrations Above the Level of the NAAQS [national ambient air quality standard] in 2010 … PM10 (24-hour) [=] 6.0"

CALCULATION: 6 million people living in counties with air quality above NAAQS / 309.3 million population = 1.9%

[103] Dataset: "National PM2.5 Emissions by Source Sector, 2008." EPA, March 18, 2012. http://www.epa.gov/...

"Particle Pollution … PM2.5 primary and secondary … Annual [=] 15 μg/m³ … annual mean, averaged over 3 years"

[106] Dataset: "PM2.5 Air Quality, 2000-2010, National Trend based on 646 Sites (Seasonally-Weighted Annual Average)." EPA, January 06, 2012. http://www.epa.gov/airtrends/pm.html

[108] Report: "Air Quality Criteria for Ozone and Related Photochemical Oxidants (Volume I of III)." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, February 28, 2006. http://oaspub.epa.gov/eims/eimscomm.getfile?p_download_id=456384

Page 3-44: "Background O3 concentrations used for purposes of informing decisions about NAAQS [National Ambient Air Quality Standards] are referred to as Policy Relevant Background (PRB) O3 concentrations. Policy Relevant Background concentrations are those concentrations that would occur in the United States in the absence of anthropogenic emissions in continental North America (defined here as the United States, Canada, and Mexico)."

"Number of People Living in Counties with Air Quality Concentrations Above the Level of the NAAQS [national ambient air quality standard] in 2010 … PM2.5 (annual and/or 24-hour) [=] 17.3"

CALCULATION: 17.3 million people living in counties with air quality above NAAQS / 309.3 million population = 5.6%

"Sulfur dioxide (SO2) is one of a group of highly reactive gasses known as 'oxides of sulfur.' "

[111] Report: "Risk and Exposure Assessment to Support the Review of the SO2 Primary National Ambient Air Quality Standards: Final Report." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division July 2009. http://www.epa.gov/...

Page 30: "[R]espiratory morbidity is the only health effect category found by the ISA [Integrated Science Assessment] to have either a causal or likely causal association with SO2."

[112] Dataset: "National Sulfur Dioxide Emissions by Source Sector, 2008." EPA, March 18, 2012. http://www.epa.gov/...

[113] Report: "Risk and Exposure Assessment to Support the Review of the SO2 Primary National Ambient Air Quality Standards: Final Report." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division July 2009. http://www.epa.gov/...

Anthropogenic [manmade] SO2 emissions originate chiefly from point sources, with fossil fuel combustion at electric utilities (~66%) and other industrial facilities (~29%) accounting for the majority of total emissions (ISA, section 2.1). Other anthropogenic sources of SO2 include both the extraction of metal from ore as well as the burning of high sulfur containing fuels by locomotives, large ships, and non-road diesel equipment. Notably, almost the entire sulfur content of fuel is released as SO2 or SO3 during combustion. Thus, based on the sulfur content in fuel stocks, oxides of sulfur emissions can be calculated to a higher degree of accuracy than can emissions for other pollutants such as PM and NO2 (ISA, section 2.1).

[115] Report: "Risk and Exposure Assessment to Support the Review of the SO2 Primary National Ambient Air Quality Standards: Final Report." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division July 2009. http://www.epa.gov/...

Page 24: "While SO2-attributable decrements in lung function have generally not been demonstrated at concentrations ≤ 1000 ppb in non-asthmatics, statistically significant increases in respiratory symptoms and decreases in lung function have consistently been observed in exercising asthmatics following 5 to 10 minute SO2 exposures at concentrations ranging from 400-600 ppb (ISA, section 4.2.1.1)."

Page 31: "As previously mentioned, the ISA's finding of a causal relationship between respiratory morbidity and short-term SO2 exposure is based in large part on results from controlled human exposure studies involving exercising asthmatics."

In addition, the ISA [Integrated Science Assessment] finds that among asthmatics, both the percentage of individuals affected, and the severity of the response increases with increasing SO2 concentrations. That is, at concentrations ranging from 200-300 ppb, the lowest levels tested in free breathing chamber studies³, 5-30% percent of exercising asthmatics experience moderate or greater decrements in lung function (ISA, Table 3-1). At concentrations ≥ 400 ppb, moderate or greater decrements in lung function occur in 20-60% of exercising asthmatics, and compared to exposures at 200-300 ppb, a larger percentage of asthmatics experience severe decrements in lung function (i.e., ≥ 200% increase in sRaw, and/or a ≥ 20% decrease in FEV1) (ISA, Table 3-1). Moreover, at SO2 concentrations ≥ 400 ppb, moderate or greater decrements in lung function are frequently accompanied by respiratory symptoms (e.g., cough, wheeze, chest tightness, shortness of breath) (Balmes et al., 1987; Gong et al., 1995; Linn et al., 1983; 1987; 1988; 1990; ISA, Table 3-1).

³ The ISA cites one chamber study with intermittent exercise where healthy and asthmatic children were exposed to 100 ppb SO2 in a mixture with ozone and sulfuric acid. The ISA notes that compared to exposure to filtered air, exposure to the pollutant mix did not result in statistically significant changes in lung function or respiratory symptoms (ISA section 3.1.3.4).

Page 36: "Human exposure studies are described in the ISA as being the 'definitive evidence' for a causal association between short-term SO2 exposure and respiratory morbidity (ISA, section 5.2). These studies have consistently demonstrated that exposure to SO2 concentrations as low as 200-300 ppb for 5-10 minutes can result in moderate or greater decrements in lung function, evidenced by a ≥15% decline in FEV1 and/or ≥ 100% increase in sRaw in a significant percentage of exercising asthmatics (see section 4.2.2)."

[117] Calculated with the dataset: "SO2 Air Quality, 1980-2010, National Trend based on 121 Sites (Annual Arithmetic Average)." EPA, January 06, 2012. http://www.epa.gov/airtrends/sulfur.html

NOTE: An Excel file containing the data and calculations is available upon request.

"Number of People Living in Counties with Air Quality Concentrations Above the Level of the NAAQS [national ambient air quality standard] in 2010 … SO2 (annual and/or 24-hour) [=] 16.7"

CALCULATION: 16.7 million people living in counties with air quality above NAAQS / 309.3 million population = 5.4%

[120] Report: "EPA's Regulation of Coal-Fired Power: Is a 'Train Wreck' Coming?" By James E. McCarthy and Claudia Copeland. Congressional Research Service, August 8, 2011. http://www.fas.org/sgp/crs/misc/R41914.pdf

On June 22, 2010, EPA revised the NAAQS [National Ambient Air Quality Standard] for SO2, focusing on short-term (1-hour) exposures. The prior standards (for 24-hour and annual concentrations), which were set in 1971, were revoked as part of the revision. Since 1971, EPA had conducted three reviews of the SO2 standard without changing it. However, following the last of these reviews, in 1998, the D.C. Circuit Court of Appeals remanded the SO2 standard to EPA, finding that the agency had failed adequately to explain its conclusion that no public health threat existed from short-term exposures to SO2.⁴³ Twelve years later, EPA revised the standard to respond to the court's decision.

The new short-term standard is substantially more stringent than the previous standards: it replaces a 24-hour standard of 140 parts per billion (ppb) with a 1-hour maximum of 75 ppb. This means that there could be an increase in the number of SO2 nonattainment areas (especially since there were no nonattainment areas under the old standards†), with additional controls required on the sources of SO2 emissions in any newly designated areas. Since electric generating units [EGUs] accounted for 60% of total U.S. emissions of SO2 in 2009, additional controls on EGUs would be likely.

The timing and extent of any additional controls is uncertain, however, for several reasons. First, the monitoring network needed to determine attainment status is incomplete and is not primarily configured to monitor locations of maximum short-term SO2 concentrations.⁴⁴ The agency says it will need 41 new monitoring sites to supplement the existing network in order to have a more complete data base. Since three years of data must be collected after a site's startup to determine attainment status, it may be as late as 2016 before some areas will have sufficient data to be classified. Even if the areas can be designated sooner based on modeling data, it would be at least 2015 before State Implementation Plans with specific control measures would be due, and actual compliance with control requirements would occur several years later.

Meanwhile, SO2 emissions will be significantly reduced as a result of the CAIR, Cross-State, and Utility MACT rules described above. Thus, although EPA identified 59 counties that would have violated the new SO2 NAAQS based on 2007-2009 data, it is not clear whether any of these counties will be in nonattainment by the time EPA designates the nonattainment areas.

† NOTE: The assertion that "there were no nonattainment areas under the old standards" is contradicted by the previous footnote, which states that there were 16.7 million people living in counties with air quality concentrations above the annual and/or 24-hour standards for SO2 in 2010. Since the newest standard (2010) is based on a 1-hour time frame, this statement cannot refer to the new standard.

"Sulfur Dioxide … primary … 1-hour [=] 75 ppb … 99th percentile of 1-hour daily maximum concentrations, averaged over 3 years"

Page 2-73: "The link between some common indoor air pollutants and health effects is very well established. Radon is a known human carcinogen and is the second leading cause of lung cancer."

Page 2-74: "Radon is a radioactive gas. It comes from the decay of uranium that is naturally occurring and commonly present in rock and soils. … [R]adon is the second leading cause of lung cancer after smoking…."

Page 2-74: "Each year, radon is associated with an estimated 21,100 lung cancer deaths in the U.S., with smokers at an increased risk; radon is the second leading cause of lung cancer after smoking, and 14.4 percent of lung cancer deaths in the U.S. are believed to be radon-related (U.S. EPA, 2003)."

It [radon] typically moves up through the ground to the air above and into a home through pathways in ground contact floors and walls. Picocuries per liter of air (pCi/L) is the unit of measure for radon in air (the metric equivalent is becquerels per cubic meter of air).

To reduce the risk of lung cancer, EPA has set a recommended "action level" of 4 pCi/L for homes. At that level, it is cost-effective for occupants to reduce their exposure by implementing preventive measures in their homes.

Page 274: "This indicator presents (1) the number of U.S. homes estimated to be at or above the EPA recommended radon action level of 4 pCi/L and (2) the number of homes with an operating radon mitigation system. The gap between the homes in these two categories is the number of homes that have not yet been mitigated (generally, homes are only mitigated if the EPA recommended radon action level of 4 pCi/L or more is measured)."

It has been reported anecdotally that radon vent fans and mitigation systems are also being used to control for soil gases and vapor intrusion in homes in the vicinity of Superfund sites, underground or aboveground storage tank sites, and similar sites as an element of corrective action plans. While radon vent fans and mitigation systems used in this way may provide a radon reduction benefit, they could be considered a subtraction from the number of homes with operating mitigation systems, thus slightly reducing the slope of the trend line.

• The indicator presumes that radon vent fans are used for their intended purpose; the available information supports this premise. Even if fans are used for managing vapor intrusion, a radon risk reduction benefit still occurs.

• A home with an operating mitigation system is presumed to have a vent fan with an average useful life of 10 years. Each year the total number of homes with operating mitigation systems is adjusted to reflect new additions and subtractions (i.e., vent fans installed 11 years earlier).

• The number of homes with radon levels at or above 4 pCi/L is an estimate based on one year of measurement data extrapolated for subsequent years based on population data, rather than on continuing measurements.

• This indicator does not track the number of homes designed and built with radon-resistant new construction features, which can help diminish radon entry in homes. Thus, more people are likely being protected from elevated indoor air exposures to radon than suggested by the trends in operating radon mitigation systems alone.

b) Dataset: "Average Number of People per Household, by Race and Hispanic Origin, Marital Status, Age, and Education of Householder: 2009." U.S. Census Bureau, January 2010.

NOTE: An Excel file containing the data and calculations is available upon request.

[127] Book: Energy and Society: An Introduction. By Harold H. Schobert. Taylor and Francis, 2002. Page 443:

If we examined rain falling in some pristine, unpolluted environment (assuming such a place still exists somewhere), we might expect it to have a pH of 7, since pure water is chemically neutral. However, carbon dioxide, a naturally occurring constituent of the environment, is slightly soluble in water. As rain falls through the air, some carbon dioxide dissolves to form the weakly acidic solution of carbonic acid

This mildly acidic solution of carbon dioxide in rainwater has a pH of 5.6. In other words, even rain falling in a completely nonpolluted environment will still have a pH of 5.6 and be mildly acidic. Therefore, only when the pH of rain is below this value can we suspect the presence of pollutants.

Small amount of other natural acids, including formic acid and acetic acid, are almost always present in rain and contribute slightly to its acidity.

[128] Book: Aquatic Pollution: An Introductory Text, Third edition. By Edward A. Laws. John Wiley & Sons, 2000. Page 540:

[A]cidic water has a pH less than 7, and basic water has a pH greater than 7. …

While it therefore might seem logical to define acid rain as any rainwater having a pH below 7, acid rain is not defined in this way. The reason stems from the fact that natural waters invariably contain some dissolved gases, including in particular CO2. …

… The pH of such a water sample would be about 5.6 to 5.7. Because of this fact, acid rain is usually defined as rainwater having a pH less than 5.6 (Colwing, 1982). In other words, a pH of 5.6 is about what one would expect if the rainwater contained no dissolved substances other than atmospheric gases. In fact, rainwater normally contains a variety of dissolved substances in addition to gases. The reason is that raindrops form on tiny atmospheric aerosols, which consist of particles of dust blown from the surface of the Earth or even salt crystals injected into the atmosphere at the surface of the ocean. Because of the presence of these other dissolved substances, the pH of rainwater may vary widely, in some cases being greater than 7 and in some cases substantially lower. … However, the pH of natural precipitation normally falls in the range of 5.0-5.6 (Wellford et al., 1982). For this reason, acid rain can be defined as rainwater having a pH less than this range rather than simply as rainwater with a pH less than 5.6.

[129] Book: Green Chemistry and Engineering: A Practical Design Approach. By Concepción Jiménez-González and David J.C. Constable. John Wiley and Sons, 2011.

Page 49: "There are multiple effects from acid deposition, including acidification of lakes and rivers, rendering them unfit for plant or animal life, accelerated decay and corrosion of buildings and property (e.g., damage to automotive paint), and indoor-quality issues. There is also damage to agricultural crops and forests, as the increased soil acidity can lead to the displacement of calcium ions and inhibit growth of plants, or plants can simply be defoliated in extreme cases of acid deposition."

You have probably heard of "acid rain." But you may not have heard of other forms of acid precipitation such as acid snow, acid fog or mist, or dry forms of acidic pollution such as acid gas and acid dust. All of these can be formed in the atmosphere and fall to Earth causing human health problems, hazy skies, environmental problems and property damage. Acid precipitation is produced when certain types of air pollutants mix with the moisture in the air to form an acid. These acids then fall to Earth as rain, snow, or fog. Even when the weather is dry, acid pollutants may fall to Earth in gases or particles.

Heavy rainstorms and melting snow can cause temporary increases in acidity in lakes and streams, primarily in the eastern United States. The temporary increases may last for days or even weeks, causing harm to fish and other aquatic life.

[131] Article: "acid rain." Encyclopædia Britannica Ultimate Reference Suite 2004.

"The process that results in the formation of acid rain generally begins with emissions into the atmosphere of sulfur dioxide and nitrogen oxide. These gases are released by automobiles, certain industrial operations (e.g., smelting and refining), and electric power plants that burn fossil fuels such as coal and oil. The gases combine with water vapour in clouds to form sulfuric and nitric acids. When precipitation falls from the clouds, it is highly acidic, having a pH value of about 5.6 or lower."

Page 14: "Sulfur dioxide (SO2) and nitrogen oxides (NOx) are the principal pollutants that cause acid precipitation. SO2 and NOx emissions released to the air react with water vapor and other chemicals to form acids that fall back to Earth. Power plants burning coal and heavy oil produce over two-thirds of the annual SO2 emissions in the United States. The majority of NOx (about 50 percent) comes from cars, buses, trucks, and other forms of transportation. About 40 percent of NOx emissions are from power plants. The rest is emitted from various sources like industrial and commercial boilers."

Nitrogen oxides are trace gases that critically affect atmospheric chemistry and aerosol formation¹. Vegetation is usually regarded as a sink for these gases, although nitric oxide and nitrogen dioxide have been detected as natural emissions from plants^2,3. Here we use in situ measurements to show that solar ultraviolet radiation induces the emission of nitrogen oxide radicals (NOx) from Scots pine (Pinus sylvestris) shoots when ambient concentrations drop below one part per billion. Although this contribution is insignificant on a local scale, our findings suggest that global NOx emissions from boreal coniferous forests may be comparable to those produced by worldwide industrial and traffic sources. …

… The cover of each chamber was made of ultraviolet-transparent quartz glass (which has a transmittance of over 90% for ultraviolet A and B light) so that the plants were exposed to solar ultraviolet radiation. …

… In previous NOx-exchange studies^3,8,9, ultraviolet radiation was excluded either by the chamber material or from the light source, causing the compensation-point estimates to be too low.

"or relating to the forest areas of the northern North Temperate Zone, dominated by coniferous trees such as spruce, fir, and pine."

"Any of various mostly needle-leaved or scale-leaved, chiefly evergreen, cone-bearing gymnospermous trees or shrubs such as pines, spruces, and firs."

Wet and dry deposition of acidic substances, which are emitted to the atmosphere by human activities, have been falling on increasingly widespread areas throughout the world in recent decades. As a result, annual precipitation averages less than pH 4.5 over large areas of the Northern Temperate Zone, and not infrequently, individual rainstorms and cloud or fog-water events have pH values less than 3. Concurrently, thousands of lakes and streams in North America and Europe have become so acidified that they no longer support viable populations of fish and other organisms.

Page 26: " Direct sources of formic acid include human activities, biomass burning and plant leaves. Aside from these direct sources, sunlight-induced oxidation of non-methane hydrocarbons (largely of biogenic origin) is probably the largest source^{3, 4}."

Although it contributes to the acidity of precipitation, formic acid is quickly consumed by microbes, so does not lead to the harmful effects of acid rain. However, formic acid has a significant effect on aqueous-phase chemistry in the atmosphere. Aqueous reactions in cloud droplets and on aerosols influence atmospheric composition, for instance through the production and loss of radicals that affect ozone, the activation of halogens and the formation of secondary organic aerosols^{3, 4, 5}. Many of these reactions are highly dependent on pH and are thus sensitive to formic acid levels.

[139] Book: Acidification in Tropical Countries. Edited by H. Rodhe and R. Herrera. John Wiley & Sons, 1988. Chapter 4: "Potential Effects of Acid Deposition on Tropical Terrestrial Ecosystems." By William H. McDowell. http://globalecology.stanford.edu/...

Page 123: "Simple organic acids of low molecular weight, especially formic and acetic acids, are important components of total acidic deposition, especially in the tropics (Keene el at., 1983), but they are not likely to be mobile within terrestrial ecosystems due to rapid decomposition. Organic acids found in wet deposition are rapidly oxidized in samples of rainwater alone (Keene et al., 1983; Keene and Galloway, 1984), and would likely be rapidly oxidized within a terrestrial ecosystem."

[140] Book: Energy and Society: An Introduction. By Harold H. Schobert. Taylor and Francis, 2002.

Page 443: "Small amount of other natural acids, including formic acid and acetic acid, are almost always present in rain and contribute slightly to its acidity."

Page 26: "Here, we use satellite measurements of formic acid concentrations to constrain model simulations of the global formic acid budget. According to our simulations, 100–120 Tg of formic acid is produced annually, which is two to three times more than that estimated from known sources. We show that 90% of the formic acid produced is biogenic in origin, and largely sourced from tropical and boreal forests. We suggest that terpenoids—volatile organic compounds released by plants—are the predominant precursors."

Page 29: "The inferred decrease in pH due to the extra HCOOH [formic acid] source is estimated at 0.25–0.5 over boreal forests in summertime, and 0.15–0.4 above tropical vegetated areas throughout the year (Supplementary Fig. S9). Our model simulations predict that formic acid alone accounts for as much as 60–80% of the rainwater acidity over Amazonia, in accordance with in situ measurements29, but also over boreal forests during summertime. Its contribution is also substantial at mid-latitudes, in particular over much of the US, where it reaches 30–50% during the summer (Supplementary Fig. S10)."

"Writing in Nature Geoscience, Stavrakou and co-workers6 use satellite measurements to investigate the global sources and sinks of atmospheric formic acid, and suggest that this acid can account for 50% or more of rainwater acidity in many continental regions of the world."

[143] Report: "Air Quality Criteria for Ozone and Related Photochemical Oxidants (Volume I of III)." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, February 28, 2006. http://oaspub.epa.gov/...

Page E-4: "Ozone (O3) is a secondary pollutant formed by atmospheric reactions involving two classes of precursor compounds, volatile organic compounds (VOCs) and nitrogen oxides (NOx). Carbon monoxide also contributes to O3 formation."

Nitrogen oxides are trace gases that critically affect atmospheric chemistry and aerosol formation1. Vegetation is usually regarded as a sink for these gases, although nitric oxide and nitrogen dioxide have been detected as natural emissions from plants2,3. Here we use in situ measurements to show that solar ultraviolet radiation induces the emission of nitrogen oxide radicals (NOx) from Scots pine (Pinus sylvestris) shoots when ambient concentrations drop below one part per billion. Although this contribution is insignificant on a local scale, our findings suggest that global NOx emissions from boreal coniferous forests may be comparable to those produced by worldwide industrial and traffic sources.

"or relating to the forest areas of the northern North Temperate Zone, dominated by coniferous trees such as spruce, fir, and pine."

"Any of various mostly needle-leaved or scale-leaved, chiefly evergreen, cone-bearing gymnospermous trees or shrubs such as pines, spruces, and firs."

"Ozone … primary and secondary … 8-hour [=] 0.075 ppm … Annual fourth-highest daily maximum 8-hr concentration, averaged over 3 years"

[148] Code of Federal Regulations, Title 40, Part 50, Appendix I: "Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone." U.S. Government Printing Office, July 1, 2011. http://www.gpo.gov/...

[149] Report: "Air Quality Criteria for Ozone and Related Photochemical Oxidants (Volume I of III)." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, February 28, 2006. http://oaspub.epa.gov/eims/eimscomm.getfile?p_download_id=456384

Page 2-24: "Ozone is ubiquitous throughout the atmosphere; it is present even in remote areas of the globe."

Page E-31: "Ozone is distributed very unevenly within the atmosphere, with ~90% of the total atmospheric burden present in the stratosphere.† The remaining ~10% is distributed within the troposphere,‡ with higher relative concentrations near the source of its precursors at the surface."

† The stratosphere is the "upper portion of the atmosphere, a nearly isothermal layer (layer of constant temperature) that is located above the troposphere. The stratosphere extends from its lower boundary of about 6 to 17 km (4 to 11 miles) altitude to its upper boundary (the stratopause) at about 50 km (30 miles)." [Article: "stratosphere." Encyclopædia Britannica Ultimate Reference Suite 2004.]

‡ The troposphere "is the layer of the atmosphere closest to Earth's surface. People live in the troposphere, and nearly all of Earth's weather-including most clouds, rain, and snow-occurs there. The troposphere contains about 80 percent of the atmosphere's mass and about 99 percent of its water." [Article: "troposphere." Encyclopædia Britannica Ultimate Reference Suite 2004.]

Background O3 concentrations used for purposes of informing decisions about NAAQS [National Ambient Air Quality Standards] are referred to as Policy Relevant Background (PRB) O3 concentrations. Policy Relevant Background concentrations are those concentrations that would occur in the United States in the absence of anthropogenic [manmade] emissions in continental North America (defined here as the United States, Canada, and Mexico).

Contributions to PRB O3 include photochemical actions involving natural emissions of VOCs, NOx, and CO as well as the long-range transport of O3 and its precursors from outside North America and the stratospheric-tropospheric exchange (STE) of O3. Processes involved in STE are described in detail in Annex AX2.3. Natural sources of O3 precursors include biogenic emissions, wildfires, and lightning. Biogenic emissions from agricultural activities are not considered in the formation of PRB O3.

Estimates of PRB concentrations cannot be obtained solely by examining measurements of O3 obtained at RRMS [relatively remote monitoring sites] in the United States … because of the long-range transport from anthropogenic [manmade] source regions within North America. It should also be noted that it is impossible to determine sources of O3 without ancillary data that could be used as tracers of sources or to calculate photochemical production and loss rates.

Page 3-48: "Lefohn et al. (2001) have argued that frequent occurrences of O3 concentrations above 50 to 60 ppbv at remote northern U.S. sites in spring are mainly stratospheric in origin."

PRB ozone is not a directly observable quantity and must therefore be estimated from models. Simple modeling approaches, such as the use of back-trajectories at remote U.S. sites to identify background conditions, are subject to errors involving the reliability of the trajectories, chemical production along the trajectories, and the hemispheric-scale contribution of North American sources to ozone in air masses originating outside the continent. They also cannot describe the geographical variability of the ozone background or the depletion of this background during pollution episodes. Global 3-D chemical transport models such as GEOS-Chem can provide physically-based estimates of the PRB and its variability through sensitivity simulations with North American anthropogenic sources shut off. These models are also subject to errors in the simulation of transport and chemistry, but the wealth of data that they provide on ozone and its precursors for the present-day atmosphere enables extensive testing with observations, and thus objective estimate of the errors on the PRB ozone values.

Page 4-54:

Figure 3-27. Time-series of hourly average O3 concentrations observed at five national parks: Denali (AK), Voyageur (MN), Olympic (WA), Glacier (MT), and Yellowstone (WY).

[150] Report: "Air Quality Criteria for Ozone and Related Photochemical Oxidants (Volume I of III)." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, February 28, 2006. http://oaspub.epa.gov/eims/eimscomm.getfile?p_download_id=456384

Policy relevant background O3 concentrations are used for assessing risks to human health associated with O3 produced from anthropogenic [manmade] sources in continental North America. Because of the nature of the definition of PRB concentrations, they cannot be directly derived from monitored concentrations, instead they must be derived from modeled estimates. Current model estimates indicate that ambient air PRB concentrations in the United States are generally 0.015 ppm to 0.035 ppm. They decline from spring to summer and are generally <0.025 ppm under conditions conducive to high O3 episodes. However, PRB concentrations can be higher, especially at elevated sites during spring, due to enhanced contributions from hemispheric pollution and stratospheric exchange.

Previous estimates of background O3 concentrations, based on different concepts of background, are given in Table 3-2. Results from global three-dimensional CTMs [chemistry transport models], where the background is estimated by zeroing anthropogenic [manmade] emissions in North America (Table 3-8) are on the low end of the 25 to 45 ppbv [parts per billion volume] range.

• PRB O3 concentrations in U.S. surface air from 1300 to 1700 local time are generally 15 to 35 ppbv. They decline from spring to summer and are generally <25 ppbv under the conditions conducive to high-O3 episodes. …

• High PRB concentrations (40 to 50 ppbv) occur occasionally at high-elevation sites (>1.5 km) in spring due to the free-tropospheric influence, including a 4- to 12-ppbv contribution from hemispheric pollution (O3 produced from anthropogenic [manmade] emissions outside North America). These sites cannot be viewed as representative of low-elevation surface sites … where the background is lower when O3 >60 ppbv.

• The stratospheric contribution to surface O3 is of minor importance, typically well <20 ppbv. While stratospheric intrusions might occasionally elevate surface O3 at high-altitude sites, these events are rare.

[151] Calculated with data from the footnote above and: "National Ambient Air Quality Standards (NAAQS)." EPA, November 08, 2011. http://www.epa.gov/air/criteria.html

"Ozone … primary and secondary … 8-hour [=] 0.075 ppm … Annual fourth-highest daily maximum 8-hr concentration, averaged over 3 years"

[152] Article: "NYC Trees Grow Larger Than Country Trees." By Rick Callahan. Associated Press, July 9, 2003. http://www.newsday.com

Scientists studying urban pollution have discovered to their amazement that trees in New York City's concrete jungle grow twice as large as those in the countryside, far from the billowing smokestacks and crowded streets.

The findings illustrate what scientists have only recently realized -- that pollution from urban areas can have its biggest effects far from cities. …

"In the country, the trees were about up to my waist. In the city, they were almost over my head -- it's really dramatic," said Jillian W. Gregg, the study's lead author. …

"No matter what soil I grew them, in they always grew twice as large in New York City," said Gregg, who was initially perplexed by the results.

Page 184: "Contrary to expectations, cottonwoods grew twice as large amid the high concentration of multiple pollutants in New York City compared to rural sites (Fig. 1). Greater urban plant biomass was found for all urban–rural site comparisons, two separate planting dates in the first year and two further consecutive growing seasons."

Page 183: "[H]igher rural ozone (O3) exposures reduced growth at rural sites. Urban precursors fuel the reactions of O3 formation, but NOx scavenging reactions7 resulted in lower cumulative urban O3 exposures compared to agricultural and forested sites throughout the northeastern USA. Our study … shows a greater adverse effect of urban pollutant emissions beyond the urban core."

Page 185: "Primary O3 precursors are emitted in cities, but must react in sunlight to form O3 as air masses move to rural environments²⁰. Ozone exposures were therefore consistently higher for rural sites both to the north and the east of the city in all consecutive growing seasons…."

Page 186: "Although individual 1- hour peak concentrations are typically higher in urban centres⁷, our data indicate that the higher cumulative exposures at rural sites had the greatest impact."

[154] Report: "Air Quality Criteria for Ozone and Related Photochemical Oxidants (Volume I of III)." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, February 28, 2006. http://oaspub.epa.gov/eims/eimscomm.getfile?p_download_id=456384

The formation of O3 and associated compounds is a complex, nonlinear function of many factors, including the intensity and spectral distribution of sunlight; atmospheric mixing and other atmospheric processes; and the concentrations of the precursors in ambient air. At lower NOx concentrations found in most environments, ranging from remote continental areas to rural and suburban areas downwind of urban centers, the net production of O3 increases with increasing NOx. At higher concentrations found in downtown metropolitan areas, especially near busy streets and highways and in power plant plumes, there is net destruction of O3 by reaction with NO. In between these two regimes, there is a transition stage in which O3 production shows only a weak dependence on NOx concentrations. The efficiency of O3 production per NOx oxidized is generally highest in areas where NOx concentrations are lowest and decrease with increasing NOx concentration.

[155] Report: "Risk and Exposure Assessment to Support the Review of the SO2 Primary National Ambient Air Quality Standards: Final Report." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division July 2009. http://www.epa.gov/...

Page 13: "There is a large amount of variability in the time that individuals spend in different microenvironments, but on average people spend the majority of their time (about 87%) indoors. Most of this time is spent at home with less time spent in an office/workplace or other indoor locations (ISA, Figure 2-36). In addition, people spend on average about 8% of their time outdoors and 6% of their time in vehicles."

[156] Report: "Air Quality Criteria for Ozone and Related Photochemical Oxidants (Volume I of III)." EPA, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division, February 28, 2006. http://oaspub.epa.gov/eims/eimscomm.getfile?p_download_id=456384

Page E-9: "Humans are exposed to O3 either outdoors or in various microenvironments. Ozone in indoor environments results mainly from infiltration from outdoors. Once indoors, O3 is removed by deposition on and reaction with surfaces and reactions with other pollutants. Hence, O3 levels indoors tend to be notably lower than outdoor O3 concentrations measured at nearby monitoring sites, although the indoor and ambient O3 concentrations tend to vary together (i.e., the higher the ambient, the higher the indoor O3 levels)."

Page 3-64: "To a lesser extent, O3 concentrations in microenvironments are influenced by the ambient temperature, time of day, indoor characteristics (e.g., presence of carpeting), and the presence of other pollutants in the microenvironment. Table 3-4 describes the findings of the available studies."

Page 3-65: "Ozone enters the indoor environment primarily through infiltration from outdoors through building components, such as windows, doors, and ventilation systems. There are also a few indoor sources of O3 (photocopiers, facsimile machines, laser printers, and electrostatic air cleaners and precipitators) (Weschler, 2000). Generally O3 emissions from office equipment and air cleaners are low except under improper maintenance conditions."

The most important removal process for O3 in the indoor environment is deposition on, and reaction with, indoor surfaces. The rate of deposition is material-specific. The removal rate will depend on the indoor dimensions, surface coverings, and furnishings. Smaller rooms generally have larger surface-to-volume ratio (A/V) and remove O3 faster than larger rooms. Fleecy materials, such as carpets, have larger surface-to-volume ratios and remove O3 faster than smooth surfaces (Weschler, 2000). However, the rate of O3 reaction with carpet diminishes with cumulative O3 exposure (Morrison and Nazaroff, 2000, 2002). Weschler (2000) compiled the O3 removal rates for a variety of microenvironments.

Other complications for O3 in the relationship between personal exposures and ambient concentrations include expected strong seasonal variation of personal behaviors and building ventilation practices that can modify exposure. In addition, the relationship may be affected by temperature (e.g., high temperature may increase air conditioning use, which may reduce O3 penetration indoors), further complicating the role of temperature as a confounder of O3 health effects. It should be noted that the pattern of exposure misclassification error and influence of confounders may differ across the outcomes of interest as well as in susceptible populations. For example, those who may be suffering from chronic cardiovascular or respiratory conditions may be in a more protective environment (i.e., with less exposure to both O3 and its confounders, such as temperature and PM) than those who are healthy.

Given the large amount of time people spend indoors, exposure to Pb in dusts and indoor air can be significant. For children, dust ingested via hand-to-mouth activity is often a more important source of Pb exposure than inhalation. Dust can be resuspended through household activities, thereby posing an inhalation risk as well. House dust Pb can derive both from Pb-based paint and from other sources outside the home. The latter include Pb-contaminated airborne particles from currently operating industrial facilities or resuspended soil particles contaminated by deposition of airborne Pb from past emissions.

Concentrations of Pb can be elevated indoors. Lead in indoor air is directly related to Pb in housedust, which poses both an inhalation and an ingestion risk and is discussed in more detail in Section 3.2. Strong correlations have been observed in a Boston study between indoor air, floor dust, and soil Pb concentrations (Rabinowitz et al., 1985a). In the National Human Exposure Assessment Survey (NHEXAS) study of six Midwestern states, Pb concentrations in personal air were significantly higher than either indoor or outdoor concentrations of air Pb (Clayton et al., 1999). The predominant sources of indoor air Pb are thought to be outdoor air and degraded Pb-based paint.

Lead concentrations tend to be somewhat elevated in houses of smokers. In a nationwide U.S. study, blood-Pb levels were 38% higher in children who exhibited high cotinine levels, which reflect high secondhand smoke exposure (Mannino et al., 2003). Lead is present both in tobacco and in tobacco smoke, although Pb concentrations in tobacco have fallen in parallel with decreases in airborne Pb concentrations (Mannino et al., 2003). …

Lead concentrations inside work places can also be elevated. Thus, inhalation of Pb during work hours is an additional route of exposure for some subpopulations. Feng and Barratt (1994) measured Pb concentrations in two office buildings in the United Kingdom (UK). In general, concentrations in the UK office buildings were higher than those in nearby houses.

Page 3-27: "Given the large amount of time people spend indoors, exposure to Pb in dusts and indoor air can be significant. For children, dust ingested via hand-to-mouth activity can be a more important source of Pb exposure than inhalation (Adgate et al., 1998; Oliver et al., 1999)."

Lead in housedust can derive from a number of different sources. Lead appears both to come from sources outside the home (Jones et al., 2000; Adgate et al., 1998) and from Pb-based paint (Hunt et al., 1993; Lanphear et al., 1996). A chemical mass balance study in Jersey City, NJ observed that crustal sources contributed almost half of the Pb in residences, Pb-based paint contributed about a third, and deposition of airborne Pb contributed the remainder (Adgate et al., 1998). Residential concentrations measured at the Bunker Hill Superfund Site in northern Idaho indicate that the Pb concentration in houses depends primarily on the neighborhood soil-Pb concentration (Von Lindern et al., 2003a, 2003b). However, factors such as household hygiene, the number of adults living in the house, and the number of hours children spend playing outside were also shown to affect Pb concentrations.

Page 3-29: "Renovation, and especially old paint removal, can greatly increase Pb levels inside the home (Laxen et al., 1987; Jacobs, 1998; Mielke et al., 2001). Removal of exterior paint via power sanding released an estimated 7.4 kg of Pb as dust, causing Pb levels inside one house to be well above safe levels (Mielke et al., 2001)."

Regardless of the study, Table 4-2 shows that the mean CO concentrations inside vehicles always exceeded the mean ambient CO concentrations measured at fixed-site monitors. The ratio between a study's mean in-vehicle CO concentration and its mean ambient CO concentration fell between 2 and 5 for most studies, regardless of when the study was done, but exceeded 5 for two studies done during the early 1980s. Of the more recent studies, Chan et al. (1991) found that median CO concentrations were 11 ppm inside test vehicles driven on hypothetical routes in Raleigh, NC, during August and September 1988, but median ambient concentrations were only 2.8 ppm at fixed-site monitors. Fixed-site samples were collected about 30 to 100 m from the midpoint of each route. …

Like earlier studies, recent ones also have looked at effects of different routes and travel modes on CO exposure. Chan et al. (1991) reported significantly different in-vehicle exposures to CO for standardized drives on three routes that varied in traffic volume and speed. The median in-vehicle CO concentration was 13 ppm for 30 samples in the downtown area of Raleigh, which had heavy traffic volumes, slow speeds, and frequent stops. The next highest concentrations (median = 11 ppm, n = 34) occurred on an interstate beltway that had moderate traffic volumes and high speeds, and the lowest concentrations (median = 4 ppm, n = 6) occurred on rural highways with low traffic volumes and moderate speeds.

Page 156: "Studies have quantified the effect of traffic volume and speed on in-vehicle CO exposure. Flachsbart et al. (1987) reported that in-vehicle CO exposures fell by 35% when test vehicle speeds increased from 10 to 60 mph on eight commuter routes in Washington."

Ice skating, motocross, and tractor pulls are sporting events in which significant quantities of CO may be emitted in short periods of time by machines in poorly ventilated indoor arenas. The CO is emitted by several sources, including ice resurfacing machines and ice edgers during skating events; gas-powered radiant heaters used to heat viewing stands; and motor vehicles at motocross, monster-truck, and tractor-pull competitions. These competitions usually involve many motor vehicles with no emission controls. Several studies of CO exposure in commercial facilities were not cited in the previous CO criteria document. First, Kwok (1981) reported episodes of CO poisoning among skaters inside four arenas in Ontario, Canada. Mean CO levels ranged from 4 to 81 ppm for periods of about 80 min. The CO levels in the spectator areas ranged from 90 to 100% of levels on the ice rinks. The ice resurfacing machines lacked catalytic emission controls. Second, both Sorensen (1986) and Miller et al. (1989) reported CO concentrations greater than 100 ppm in rinks from the use of gasoline-powered resurfacing machines. High concentrations were attributed to poorly maintained machines and insufficient ventilation in one rink. …

In the United States, surveys of CO exposure were done at ice arenas in Vermont, Massachusetts, Wisconsin, and Washington. For a rink in Massachusetts, Lee et al. (1993) showed that excessive CO concentrations can occur even with well-maintained equipment and fewer resurfacing operations if ventilation is inadequate. Average CO levels were less than 20 ppm over 14 h, with no significant source of outdoor CO. Ventilation systems could not disperse pollutants emitted and trapped by temperature inversions and low air circulation at ice level. In another study, Lee et al. (1994) reported that CO concentrations measured inside six enclosed rinks in the Boston area during a 2-h hockey game ranged from 4 to 117 ppm, whereas outdoor levels were about 2 to 3 ppm, and the alveolar CO of hockey players increased by an average of 0.53 ppm per 1 ppm CO exposure over 2 h. Fifteen years earlier, Spengler et al. (1978) found CO levels ranging from 23 to 100 ppm in eight enclosed rinks in the Boston area, which suggests that CO exposure levels in ice arenas have not improved. …

Studies also have been done in sports arenas that allow motor vehicles. Boudreau et al. (1994) reported CO levels for three indoor sporting events (i.e., monster-truck competitions, tractor pulls) in Cincinnati. The CO measurements were taken before and during each event at different elevations in the public seating area of each arena with most readings obtained at the midpoint elevation where most people were seated. Average CO concentrations over 1 to 2 h ranged from 13 to 23 ppm before the event to 79 to 140 ppm during the event. Measured CO levels were lower at higher seating levels. The ventilation system was operated maximally, and ground-level entrances were completely open.

Given that the pNEM/CO exposure model accounts for the passive exposure of nonsmokers to CO concentrations from smoking, this section briefly reviews two studies of this type. In April 1992, Ott et al. (1992b) took continuous readings of CO concentrations inside a passenger car for an hour-long trip through a residential neighborhood of the San Francisco Bay Area. Measurements were taken in both the front and back seats of the vehicle as a passenger smoked cigarettes. The neighborhood had low ambient CO levels, because it had little traffic and few stop signs. During the trip, the air conditioning system was operated in the recirculation mode. Concentrations in the front and rear seats were similar indicating that CO concentrations were well mixed throughout the passenger compartment. CO concentrations reached a peak of 20 ppm after the third cigarette. Using the breath measurement technique of Jones et al. (1958), the breath CO level of the driver (a nonsmoker) increased from 2 ppm before the trip to 9.2 ppm at the end of the trip.

Indoor and in-transit concentrations of CO can be significantly different from the typically low ambient CO concentrations. The CO levels in homes without combustion sources are usually lower than 5 ppm. The highest residential concentrations of CO that have been reported are associated with vehicle startup and idling in attached garages and the use of unvented gas or kerosene space heaters where peak concentrations of CO as high or higher than 50 ppm have been reported. Carbon monoxide concentrations also have exceeded 9 ppm for 8 h in several homes with gas stoves and, in one case, 35 ppm for 1 h; however, these higher CO concentrations were in homes with older gas ranges that had pilot lights that burn continuously. Newer or remodeled homes have gas ranges with electronic pilot lights. Also, the availability of other cooking appliances (e.g., microwaves, heating plates) has decreased the use of gas ranges in meal preparation.

Page 282: "Evaluation of human CO exposure situations indicates that occupational exposures in some workplaces, or exposures in homes with faulty or unvented combustion sources, can exceed 100 ppm CO, leading to COHb levels of 4 to 5% with 1-h exposure and 10% or more with continued exposure for 8 h or longer (see Table 7-1). Such high exposure levels are encountered rarely by the general public under ambient conditions."

Page 283: "Putting the ambient CO levels into perspective, exposures to cigarette smoke or to combustion exhaust gases from small engines and recreational vehicles typically raise COHb to levels much higher than levels resulting from mean ambient CO exposures, and, for most people, exposures to indoor sources of CO often exceed controllable outdoor exposures."

The Congress establishes for purposes of this section a list of hazardous air pollutants as follows: …

The Administrator shall periodically review the list established by this subsection and publish the results thereof and, where appropriate, revise such list by rule, adding pollutants which present, or may present, through inhalation or other routes of exposure, a threat of adverse human health effects (including, but not limited to, substances which are known to be, or may reasonably be anticipated to be, carcinogenic, mutagenic, teratogenic, neurotoxic, which cause reproductive dysfunction, or which are acutely or chronically toxic) or adverse environmental effects whether through ambient concentrations, bioaccumulation, deposition, or otherwise, but not including releases subject to regulation under subsection (r) of this section as a result of emissions to the air.

(A) Beginning at any time after 6 months after November 15, 1990, any person may petition the Administrator to modify the list of hazardous air pollutants under this subsection by adding or deleting a substance or, in case of listed pollutants without CAS numbers (other than coke oven emissions, mineral fibers, or polycyclic organic matter) removing certain unique substances. Within 18 months after receipt of a petition, the Administrator shall either grant or deny the petition by publishing a written explanation of the reasons for the Administrator's decision. Any such petition shall include a showing by the petitioner that there is adequate data on the health or environmental defects [2] of the pollutant or other evidence adequate to support the petition. The Administrator may not deny a petition solely on the basis of inadequate resources or time for review. …

The Administrator shall promulgate regulations establishing emission standards for each category or subcategory of major sources and area sources of hazardous air pollutants listed for regulation pursuant to subsection (c) of this section in accordance with the schedules provided in subsections (c) and (e) of this section.

People exposed to toxic air pollutants at sufficient concentrations and durations may have an increased chance of getting cancer or experiencing other serious health effects. These health effects can include damage to the immune system, as well as neurological, reproductive (e.g., reduced fertility), developmental, respiratory and other health problems. In addition to exposure from breathing air toxics, some toxic air pollutants such as mercury can deposit onto soils or surface waters, where they are taken up by plants and ingested by animals and are eventually magnified up through the food chain. Like humans, animals may experience health problems if exposed to sufficient quantities of air toxics over time.

Page 2-48: "Toxic air pollutants, also known as air toxics or hazardous air pollutants (HAPs), are those pollutants that are known or suspected to cause cancer or are associated with other serious health (e.g., reproductive problems, birth defects) or ecological effects."

Emissions standards promulgated under this subsection and applicable to new or existing sources of hazardous air pollutants shall require the maximum degree of reduction in emissions of the hazardous air pollutants subject to this section (including a prohibition on such emissions, where achievable) that the Administrator, taking into consideration the cost of achieving such emission reduction, and any non-air quality health and environmental impacts and energy requirements, determines is achievable for new or existing sources in the category or subcategory to which such emission standard applies, through application of measures, processes, methods, systems or techniques including, but not limited to, measures which—

(A) reduce the volume of, or eliminate emissions of, such pollutants through process changes, substitution of materials or other modifications,

(D) are design, equipment, work practice, or operational standards (including requirements for operator training or certification) as provided in subsection (h) of this section, or

Page 29: "For the six principal [criteria] pollutants, a variety of control strategies are used in geographic areas where the national air quality standards have been violated. In contrast, for toxic air pollutants, EPA has focused on identifying all major sources that emit these pollutants and developing national technology-based performance standards to significantly reduce their emissions. The objective is to ensure that major sources of toxic air pollution are well controlled regardless of geographic location."

[165] Report: "Comparison of ASPEN [Assessment System for Population Exposure Nationwide] Modeling System Results to Monitored Concentrations." EPA, April 15, 2010. http://www.epa.gov/ttn/atw/nata/draft6.html

Unlike for criteria air pollutants, there currently is no formal national air toxics monitoring network which follows standardized EPA guidelines or established national monitoring procedures. While several States and local agencies have collected some high quality HAP monitoring data, some of the data have not undergone any formal quality assurance tests, and the data come from several different monitoring networks which may vary in precision and accuracy. In general, we would expect the precision and accuracy of air toxics monitoring data to be not nearly as good as the SO2 and particulate matter monitoring data used in the studies in the previous section. We will discuss some of the other monitoring uncertainties in more detail below.

[166] Manual: Air Toxics Risk Assessment Reference Library, Volume 1. Prepared by ICF Consulting for the EPA, Office of Air Quality Planning and Standards, Emissions Standards Division, April 2004. Chapter 2: "Clean Air Act Requirements and Programs to Regulate Air Toxics." http://www.epa.gov/ttn/fera/data/risk/vol_1/chapter_02.pdf

Page 2-1: "EPA has set National Ambient Air Quality Standards (NAAQS) for these pollutants [criteria pollutants] based on health and welfare-related criteria…. No such national ambient air quality standards currently exist for HAPs, although regulatory programs are in place to address emissions of HAPs."

Page 2-48: "Air toxics emissions data are tracked by the National Emissions Inventory (NEI). The NEI is a composite of data from many different sources, including industry and numerous state, tribal, and local agencies. Different data sources use different data collection methods, and many of the emissions data are based on estimates rather than actual measurements."

Page 2-49: "The emissions data are largely based on estimates. Although these estimates are generated using well-established approaches, the estimates have inherent uncertainties. The methodology for estimating emissions is continually reviewed and is subject to revision. Trend data prior to any revisions must be considered in the context of those changes."

"EPA is working with state, local, and tribal governments to reduce air toxics releases of 188 pollutants to the environment. Examples of toxic air pollutants include benzene, which is found in gasoline; perchloroethylene, which is emitted from some dry cleaning facilities; and methylene chloride, which is used as a solvent and paint stripper by a number of industries. Examples of other listed air toxics include dioxin, asbestos, toluene, and metals such as cadmium, mercury, chromium, and lead compounds."

In addition to presenting emissions data aggregated across all 188 air toxics, the indicator presents emissions trends for five individual air toxics: acrolein, benzene, 1,3-butadiene, ethylene dibromide, and hydrazine. These compounds were selected for display because EPA's 1999 National Air Toxics Assessment estimates that they present the greatest nationwide health risks (whether for cancer or non-cancer endpoints) among the subset of air toxics for which available emissions and toxicity data supported an evaluation (U.S. EPA, 2006).

Exhibit 2-42 shows emissions trends for five compounds believed to account for the greatest health risks that are attributed to air toxics, according to a recent modeling study (U.S. EPA, 2006). …

There is uncertainty associated with identifying which air toxics account for the greatest health risk nationwide. Toxicity information is not available for every compound, and emissions and exposure estimates used to characterize risk have inherent uncertainties. Additional limitations associated with the National Air Toxics Assessment are well documented (U.S. EPA, 2006).

NEI [National Emissions Inventory] data have been collected since 1990 and cover all 50 states and their counties, D.C., the U.S. territories of Puerto Rico and the Virgin Islands, and some of the territories of federally recognized American Indian nations. The NEI includes baseline air toxics data for the 1990-1993 period and since then has been updated every 3 years. The baseline period represents a mix of years depending on data availability for various source types. While NEI data for air toxics were also compiled for 1996 and 1999, the methodology used in those years for air toxics differed considerably from the methodology that was used in 2002. Therefore, the 1996 and 1999 data are not presented because comparing the two inventories might lead to invalid conclusions.

NOTE: An Excel file containing the data and calculations is available upon request.

Page 2-49: "The indicator is an aggregate number that represents contributions from 188 different chemicals with widely varying toxicities and human exposures. Therefore, the nationwide trend for total air toxics and the resulting health effects likely differs from emissions trends for specific chemicals. Similarly, because the indicator is a nationwide aggregate statistic, the trend may not reflect emissions trends for specific locations."

NOTE: An Excel file containing the data and calculations is available upon request.

Page 13: "Wetlands—areas that are periodically saturated or covered by water—are an important ecological resource. Wetlands are like sponges, with a natural ability to store water. They act as buffers to flooding and erosion, and they improve the quality of water by filtering out contaminants. Wetlands also provide food and habitat for many plants and animals, including rare and endangered species. In addition, they support activities such as commercial fishing and recreation."

Page 14: "Coastal waters—the interface between terrestrial environments and the open ocean—encompass many unique habitats such as estuaries, coastal wetlands, seagrass meadows, coral reefs, and mangrove and kelp forests. These ecologically rich areas support waterfowl, fish, marine mammals, and many other organisms."

[176] Report: "National Coastal Condition Report IV." EPA, Office of Research and Development, Office of Water, April 2012. http://water.epa.gov/...

Page 1: "Estuaries are bodies of water that receive freshwater and sediment influx from rivers and tidal influx from the oceans, thus providing transition zones between the fresh water of a river and the saline environment of the sea."

"An underground layer of permeable rock, sediment (usually sand or gravel), or soil that yields water. The pore spaces in aquifers are filled with water and are interconnected, so that water flows through them. Sandstones, unconsolidated gravels, and porous limestones make the best aquifers. They can range from a few square kilometers to thousands of square kilometers in size."

[178] Report: "The Foundation for Global Action on Persistent Organic Pollutants: A United States Perspective." EPA, Office of Research and Development, March 2002. Page 1-6:

Bioaccumulation is the phenomenon whereby a chemical reaches a greater concentration in the tissues of an organism than in the surrounding environment (water, sediment, soil, air), principally through respiratory and dietary uptake routes. … The magnitude of bioaccumulation is driven by the hydrophobicity, or water insolubility, of the chemical, principally operating through the ability of a species to eliminate the chemical from its body by excretion and/or metabolism.

Mercury exists in a number of inorganic and organic forms in water. Methylmercury, the most common organic form of mercury, quickly enters the aquatic food chain. In most adult fish, 90% to 100% of the mercury is methylmercury. Methylmercury is found primarily in the fish muscle (fillets) bound to proteins. Skinning and trimming the fish does not significantly reduce the mercury concentration in the fillet, nor is it removed by cooking processes. Because moisture is lost during cooking, the concentration of mercury after cooking is actually higher than it is in the fresh uncooked fish.

Once released into the environment, inorganic mercury is converted to organic mercury (methylmercury) which is the primary form that accumulates in fish and shellfish. Methylmercury biomagnifies up the food chain as it is passed from a lower food chain level to a subsequently higher food chain level through consumption of prey organisms or predators. Fish at the top of the aquatic food chain, such as pike, bass, shark and swordfish, bioaccumulate methylmercury approximately 1 to 10 million times greater than dissolved methylmercury concentrations found in surrounding waters.

The chemicals, however, biologically accumulate (bioaccumulate) in the organism and become concentrated at levels that are much higher than in the surrounding water. Small fish and zooplankton consume vast quantities of phytoplankton. In doing so, any toxic chemicals accumulated by the phytoplankton are further concentrated in their bodies. These concentrations are increased at each level in the food chain. This process of increasing pollutant concentration through the food chain is called biomagnification. The top predators in a food chain, such as lake trout, coho and chinook salmon, and fish-eating gulls, herons, and bald eagles, may accumulate concentrations of a toxic chemical high enough to cause serious deformities or death or to impair their ability to reproduce. The concentration of some chemicals in the fatty tissues of top predators can be millions of times higher than the concentration in the surrounding water.

[181] Fact Sheet: "Polychlorinated Biphenyls (PCBs) Update: Impact on Fish Advisories." EPA, Office of Water, September 1999. http://water.epa.gov/...

PCBs are a group of synthetic organic chemicals that contain 209 possible individual chlorinated biphenyl compounds. These chemically related compounds are called congeners and vary in their physical and chemical properties and toxicity. There are no known natural sources of PCBs. Although banned in the United States from further production in 1979, PCBs are distributed widely in the environment because of their persistence and widespread use. …

PCBs are highly lipophilic (fat soluble) and are rapidly accumulated by aquatic organisms and bioaccumulated through the aquatic food chain. Concentrations of PCBs in aquatic organisms may be 2,000 to more than a million times higher than the concentrations found in the surrounding waters, with species at the top of the food chain having the highest concentrations.

[182] Fact Sheet: Polychlorinated Dibenzo-p-dioxins and Related Compounds Update: Impact on Fish Advisories." EPA, Office of Water, September 1999. http://water.epa.gov/...

Dioxins are a group of synthetic organic chemicals that contain 210 structurally related individual chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs). For the purposes of this fact sheet, the term "dioxins" will refer to the aggregate of all CDDs and CDFs. These chemically related compounds vary in their physical and chemical properties and toxicity. Dioxins have never been intentionally produced, except in small quantities for research. They are unintentionally produced as byproducts of incineration and combustion processes, chlorine bleaching in pulp and paper mills, and as contaminants in certain chlorinated organic chemicals. They are distributed widely in the environment because of their persistence. Dioxin exposure is associated with a wide array of adverse health effects in experimental animals, including death. Experimental animal studies have shown toxic effects to the liver, gastrointestinal system, blood, skin, endocrine system, immune system, nervous system, and reproductive system. In addition, developmental effects and liver cancer have been reported. …

Dioxins in surface waters and sediments are accumulated by aquatic organisms and bioaccumulated through the aquatic food chain. Concentrations of dioxins in aquatic organisms may be hundreds to thousands of times higher than the concentrations found in the surrounding waters or sediments. Bioaccumulation factors vary among the congeners and generally increase with chlorine content up through the tetra congeners and then generally decrease with higher chlorine content.

[183] Report: "National Study of Chemical Residues in Lake Fish Tissue." By Leanne Stahl and others. EPA, Office of Water, Office of Science and Technology, September 2009. http://water.epa.gov/...

This study is a national screening-level survey of chemical residues in fish tissue from lakes and reservoirs in the conterminous United States (lower 48 states), excluding the Laurentian Great Lakes and Great Salt Lake. It is unique among earlier fish monitoring efforts in the United States because the sampling sites were selected according to a statistical (random) design. Study results allow EPA to estimate the percentage of lakes and reservoirs in the United States with chemical concentrations in fish tissue that are above levels of potential concern for humans or for wildlife that eat fish. This survey also includes the largest set of chemicals ever studied in fish. Whole fish and fillets were analyzed for 268 persistent, bioaccumulative, and toxic (PBT) chemicals, including mercury, arsenic, dioxins and furans, the full complement of polychlorinated biphenyl (PCB) congeners, and a large number of pesticides and semivolatile organic compounds.

The National Lake Fish Tissue Study focused on lakes and reservoirs (hereafter referred to collectively as lakes) for two reasons: they occur in a variety of landscapes where they can receive and accumulate contaminants from several sources (including direct discharges into water, air deposition, and agricultural or urban runoff) and there is usually limited dilution of contaminants compared to flowing streams and rivers. …

This study applied a statistical or probability-based sampling approach so that results could be used to describe fish tissue contaminant concentrations in lakes on a national basis. The Nation's lakes were divided into six size categories based on surface area. Assigning different probabilities to each category prevented small lakes from dominating the group of lakes selected for sampling. It also allowed a similar number of lakes to be selected in each size category.

For this study, a lake is defined as a permanent body of water with a permanent fish population that has a surface area of at least one hectare (2.47 acres), a depth of at least one meter (3.28 feet), and at least 1,000 square meters of open, unvegetated water. The lower 48 states contain an estimated 147,000 lakes meeting these criteria (i.e., the target population). A list of candidate lakes was randomly selected from the target population for this study. From this list, EPA identified 500 sites that were accessible and appropriate for fish collection.

After a brief pilot in the fall of 1999 to test sampling logistics, EPA and its partners began full-scale fish sampling in 2000 and continued sampling annually through 2003. Each year of the study, field sampling teams collected fish from about 125 different lakes distributed across the lower 48 states. These teams applied consistent methods nationwide to collect composite samples of a predator fish species (e.g., bass or trout) and a bottom-dwelling species (e.g., carp or catfish) from each lake or reservoir. EPA identified twelve target predator species and six target bottom-dwelling species to limit the number of species included in the study.

Page xiv: "EPA analyzed different tissue fractions for predator composites (fillets) and bottom-dweller composites (whole bodies) to obtain chemical residue data for the 268 target chemicals. Analyzing fish fillets provides information for human health, while whole-body analysis produces information for ecosystem health. … Resulting fish tissue concentrations were reported on a wet weight basis."

Mercury and PCBs were detected in all the fish samples collected from the 500 sampling sites. … Forty-three of the 268 target chemicals were not detected in any samples, including all nine organophosphate pesticides (e.g., chlorpyriphos and diazinon), one PCB congener (PCB-161), and 16 of the 17 polycyclic aromatic hydrocarbons (PAHs) analyzed as semivolatile organic chemicals. There were also seventeen other semivolatile organic chemicals that were not detected.

In reporting the analytical results for this study, it is important to distinguish between detection and presence of a chemical in a fish tissue sample. Estimates of fish tissue concentrations ranging from the method detection limit (MDL) to the minimum level of quantitation (ML) are reported as being present with a 99% level of confidence. However, if a chemical is reported as "not detected" at the MDL level, there is a 50% possibility that the chemical may be present. Therefore, results for chemicals not detected in the fish tissue samples are reported as less than the MDL rather than zero.

According to EPA's 2008 Biennial National Listing of Fish Advisories, mercury, PCBs, dioxins and furans, DDT, and chlordane accounted for 97% of the advisories in effect at the end of 2008. These five chemicals were also commonly detected in fish samples collected for the National Lake Fish Tissue Study. Since human health screening values (SVs) were readily available, they were applied to total concentrations of mercury, PCBs, dioxins and furans, DDT, and chlordane found in predator fillets. The mercury SV is the tissue-based water quality criterion published by EPA in 2001. All other SVs are risk-based consumption limits published in 2000 in EPA's Guidance for Assessing Chemical Contaminant Data for Use in Fish Consumption Limits, Third Edition. Specifically, the applied SVs are the upper limit of the four-meal-per-month concentration range for the conservative consumption limit (where tissue concentrations are available for both cancer and noncancer health endpoints). If available, wildlife criteria could be applied in the same manner to interpret the whole-body data from analysis of bottom-dweller samples.

• 48.8% of the sampled population of lakes had mercury tissue concentrations that exceeded the 300 ppb (0.3 ppm) human health SV for mercury, which represents a total of 36,422 lakes.

• 16.8% of the sampled population of lakes had total PCB tissue concentrations that exceeded the 12 ppb human health SV, which represents a total of 12,886 lakes.

• 7.6% of the sampled population of lakes had dioxin and furan tissue concentrations that exceeded the 0.15 ppt [toxic equivalency or TEQ] human health SV, which represents a total of 5,856 lakes.

• 1.7% of the sampled population of lakes had DDT tissue concentrations that exceeded the 69 ppb human health SV, which represents a total of 1,329 lakes.

• 0.3% of the sampled population of lakes had fish tissue concentrations that exceeded the 67 ppb human health SV for chlordane, which represents a total of 235 lakes.

Page 12: "These field teams collected the majority of the fish samples during the summer and fall of each sampling year. This schedule coincided with the peak period for recreational fishing activity and allowed sampling teams to avoid the spawning period for most target species."

[184] Fact Sheet: Polychlorinated Dibenzo-p-dioxins and Related Compounds Update: Impact on Fish Advisories." EPA, Office of Water, September 1999. http://water.epa.gov/...

Page 1: "Dioxins are a group of synthetic organic chemicals that contain 210 structurally related individual chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs). For the purposes of this fact sheet, the term "dioxins" will refer to the aggregate of all CDDs and CDFs."

Page 28: "Specifically, the report screening values are the upper limit of the four-meal-per-month concentration range for the more conservative consumption limit where tissue concentrations are available for both cancer and noncancer health endpoints."

[185] Report: "National Coastal Condition Report IV." EPA, Office of Research and Development, Office of Water, April 2012. http://water.epa.gov/...

Page ES-2: "This assessment is based primarily on the EPA's NCA [National Coastal Assessment] data collected between 2003 and 2006."

Page ES-15: "Because this assessment is a 'snapshot' of the environment at the time the measurements were collected, some of the uncertainly associated with the measurements is difficult to quantify. Weather impacts such as droughts, floods, and hurricanes can affect results for weeks to months, in addition to normal sampling variability."

Page ES-15: "Nearly 75% by area of all the coastal waters, including the bays, sounds, and estuaries in the United States, is located in Alaska, and no national report on coastal condition can be truly complete without information on the condition of the living resources and use attainment of these waters. For this report, coastal monitoring data were only available for the southeastern region of Alaska…."

Page 1-9: "Southeastern Alaska's coastal waters … represent 63% of Alaska's total coastline…."

[F]ish sampling was conducted at all monitoring stations where this activity was feasible. At all sites where sufficient fish tissue was obtained, contaminant burdens were determined in fillet or whole-body samples. The target species typically included demersal (bottom-dwelling) and slower-moving pelagic (water column-dwelling) species (e.g., finfish, shrimp, lobster, crab, sea cucumbers…) that are representative of each of the geographic regions (Northeast Coast, Southeast Coast, Gulf Coast, West Coast, Southeastern Alaska, American Samoa, and Guam). These intermediate, trophic-level (position in the food web) species are often prey for larger predatory fish of commercial value (Harvey et al., 2008). Where available, 4 to 10 individual fish from each target species at each sampling site were analyzed by compositing fish tissues from the same species.

Although the EPA risk-based advisory guidance values were developed to evaluate the health risks of consuming market-sized fish fillets, they also may be used to assess the risk of contaminants in whole-body fish samples as a basis for estimating advisory determinations—an approach currently used by many state fish advisory programs (U.S. EPA, 2000c). Under the NCA program, EPA is also using these advisory guidance values as surrogate benchmark values for fish health in the absence of comprehensive ecological thresholds for contaminant levels in juvenile and adult fish. …

Page 123: "The rating for each site was based on the measured concentrations of these contaminants within the fish tissue samples…. The fish tissue contaminants index regional rating was based on percent of sites rather than percent area because target fish species were not caught at a large proportion of sites in each region, which invalidated the computation of percent area and associated uncertainty."

Page 1-24: "Cutpoints for Determining the Fish Tissue Contaminants Index by Station … Rating … Poor: For at least one chemical contaminant listed in Table 1-21, the measured concentrations in fish tissue exceeds the maximum value in the range of the EPA Advisory Guidance values for risk-based consumption associated with four 8-ounce meals per month."

The NCA [National Coastal Assessment] analyzes both juvenile and adult fish, most often as whole specimens, because this is the way fish would typically be consumed by predator species. This approach is appropriate for an ecological assessment. In contrast, most state programs assess the risk of contaminant exposure to human populations and, therefore, analyze primarily the fillet tissue (portion most commonly consumed by the general population). … The use of whole-fish samples can result in higher concentrations of those contaminants (e.g., … (DDT), PCBs, dioxins and other chlorinated pesticides) that are stored in fatty tissues and lower concentrations of contaminants (e.g., mercury) that accumulate primarily in the muscle tissue.

Figure 2-10 shows that 13% of all stations where fish were caught demonstrated contaminant concentrations in fish tissues above EPA Advisory Guidance values and were rated poor. The NCA examined whole-body composite samples, as well as fillets (typically 4 to 10 fish of a target species per station), for specific contaminants from 1,623 stations throughout the coastal waters of the United States (excluding Hawaii, Puerto Rico, and the U.S. Virgin Islands). Stations in poor and fair condition were dominated by samples with elevated concentrations of total PCBs, total DDT, total PAHs, and mercury.

[186] Report: "National Coastal Condition Report IV." EPA, Office of Research and Development, Office of Water, April 2012. http://water.epa.gov/...

The fish tissue contaminants index for the Northeast Coast region is rated fair to poor based on concentrations of chemical contaminants found in composites of whole-body fish, lobster, and fish fillet samples. Twenty percent of the sites sampled where fish were caught were rated poor, and an additional 20% were rated fair based on comparison to EPA advisory guidance values (Figure 3-8). The poor sites were largely congregated in Great Bay, NH; Narragansett Bay, RI; Long Island Sound; NY/NJ Harbor; and the upper Delaware Estuary. Elevated concentrations of PCBs were responsible for the impaired ratings for a large majority of sites. Moderate to high levels of DDT were detected in samples collected from sites located in the Hudson, Passaic, and Delaware rivers, and moderate mercury contamination was evident in samples collected from sites in Great Bay, NH; Narragansett Bay, RI; and the Hudson River.

[187] Report: "National Coastal Condition Report IV." EPA, Office of Research and Development, Office of Water, April 2012. http://water.epa.gov/...

The fish tissue contaminants index for the coastal waters of the Gulf Coast region is rated good, with 9% of all sites where fish were sampled rated poor for fish tissue contaminant concentrations (Figure 5-10). Contaminant concentrations exceeding EPA advisory guidance values in Gulf Coast samples were observed primarily in Atlantic croaker and hardhead catfish. Commonly observed contaminants included total PAHs, PCBs, DDT, mercury, and arsenic. Although many of the Gulf Coast estuarine and coastal areas do have fish consumption advisories in effect, that advice primarily concerns recreational game fish such as king mackerel, which are not sampled by the NCA program.

[188] Report: "National Coastal Condition Report IV." EPA, Office of Research and Development, Office of Water, April 2012. http://water.epa.gov/...

Analysis of chemical contaminants in fish tissues was performed on whole-fish composites from 55 samples of four fish species collected from 50 West Coast coastal-ocean stations. Fish were collected from 21 stations in Washington, 20 in Oregon, and 9 in California. The fish species selected for analysis were Pacific sanddab (Citharichthys sordidus), speckled sanddab (Citharichthys stigmaeus), butter sole (Isopsetta isolepis), and Dover sole (Microstomus pacificus). Concentrations of a suite of metals, pesticides, and PCBs were compared to risk-based EPA advisory guidelines for recreational fishers (U.S. EPA, 2000c).

None of the 50 stations where fish were caught would have been rated poor based on NCA cutpoints. Nine stations had cadmium concentrations between the corresponding lower and upper endpoints, and one station had total PCB concentrations between these endpoints. Therefore, these10 stations would be rated fair based on the NCA cutpoints (see Table 1-21). The remaining 40 stations had concentrations of contaminants below corresponding lower endpoints and would be rated good based on the NCA cutpoints. Based on the NCA Fish Tissue Contaminants Index (see Table 1-22) the overall offshore region would receive the same rating, good, as the West Coast coastal waters.

[189] Report: "National Coastal Condition Report IV." EPA, Office of Research and Development, Office of Water, April 2012. http://water.epa.gov/...

Page 8-8: "The fish tissue contaminants index for the coastal waters of Southeastern Alaska is rated good, with 6% of the stations where fish were caught rated fair and none of the stations rated poor (Figure 8-8)."

[190] Report: "National Coastal Condition Report IV." EPA, Office of Research and Development, Office of Water, April 2012. http://water.epa.gov/...

Page 9-5: "The fish tissue contaminants index for American Samoa is rated good based on fish tissue samples collected at 47 sites. The fish tissue contaminants index is rated poor at 4% of the sites at which fish were caught due to concentrations of PAHs and mercury in fish tissue (Figure 9-7)."

[191] Report: "National Coastal Condition Report IV." EPA, Office of Research and Development, Office of Water, April 2012. http://water.epa.gov/...

Page 9-15: "The fish tissue contaminants index for Guam is rated good, with 100% of the stations where fish were caught rated good (Figure 9-15). The fish tissue contaminant index rating is considered provisional because data are available for only 28 stations. Additionally, it is worth noting that only one sample was collected from some of the areas where contaminants have historically been present in Guam's waters (e.g., Apra Harbor and Cocos Lagoon)."

Page 6: "While the majority of surface and ground waters in the U.S. meet regulatory standards, a significant portion of monitored surface waters contains fecal bacterial densities that exceed the levels established by state surface water quality standards."

Approximately 13% of surface waters in the United States do not meet designated use criteria as determined by high densities of fecal indicator bacteria. Although some of the contamination is attributed to point sources such as confined animal feeding operation (CAFO) and wastewater treatment plant effluents, nonpoint sources are believed to contribute substantially to water pollution. Microbial source tracking (MST) methods have recently been used to help identify nonpoint sources responsible for the fecal pollution of water systems.

The Clean Water Act establishes that the states must adopt water quality standards that are compatible with pollution control programs to reduce pollutant discharges into waterways. In many cases the standards have been met by the significant reduction of loads from point sources under the National Pollutant Discharge Elimination System (NPDES). Point sources are defined as "any discernable, confined and discrete conveyance, including but not limited to any pipe, ditch or concentrated animal feeding operation from which pollutants are or may be discharged". However, more than 30 years after the Clean Water Act was implemented, a significant fraction of the U.S. rivers, lakes, and estuaries continue to be classified as failing to meet their designated uses due to the high levels of fecal bacteria (USEPA 2000b). As a consequence, protection from fecal microbial contamination is one of the most important and difficult challenges facing environmental scientists trying to safeguard waters used for recreation (primary and secondary contact), public water supplies, and propagation of fish and shellfish. …

Microbiological impairment of water is assessed by monitoring concentrations of fecal-indicator bacteria such as fecal coliforms and enterococci (USEPA 2000a). These microorganisms are associated with fecal material from humans and other warm-blooded animals and their presence in water is used to indicate potential presence of enteric pathogens that could cause illness in exposed persons (Dufour, 1984). Fecally contaminated waters not only harbor pathogens and pose potential high risks to human health, but they also result in significant economic loss due to closure of shellfish harvesting areas and recreational beaches (Rabinovici et al., 2004). For effective management of fecal contamination to water systems, the sources must be identified prior to implementing remediation practices.

[193] Article: "Wildlife Waste Is Major Water Polluter, Studies Say." By David A. Fahrenthold. Washington Post, September 29, 2006. http://www.washingtonpost.com/...

NOTE: Credit for bringing this article to attention belongs to Stephen F. Hayward & Amy Kaleita of the Pacific Research Institute. (Report: "Index of Leading Environmental Indicators." Twelfth edition, 2007. http://liberty.pacificresearch.org/docLib/20070418_07EnvIndex.pdf)

Case 1. St. Andrews Park (Georgia) Source of information: Hartel, P., K. Gates, and K. Payne. 2004. Targeted sampling of St. Andrews Park on Jekyll Island to determine sources of fecal contamination …

Summary of results and conclusions. During calm weather, highest concentrations of enterococci were detected in the upper reaches of Beach Creek, the sediments of the creek, and the bathing area. Species composition in creek sediments and bathing area sediments were different, which was taken to indicate effects by different enterococci sources. The large proportion of E. faecalis in the upper reaches of Beach Creek was interpreted to implicate wild birds or humans as a source. The conclusion that wild birds, not humans, were a major source in the upper reaches of Beach Creek was supported by the marshy character of the area, which makes a human source unlikely at that location. Though there was no statistical correlation between turbidity and enterococci concentration, co-incidence of high enterococci concentrations and high turbidity in windy weather was taken as evidence that sediments were a source of elevated water-column numbers during windy weather.

Human-specific adhesin factor was not detected in any of 200 isolates tested. This was interpreted as evidence that human sources were not major contributors of enterococci to the test area. However, the incidence rate of the human-specific marker in enterococci colonizing the human population is unknown, and there was no mention of a positive control in marker detection by the research method used, which might limit the interpretability of this result. Human population size, local approaches to control human waste, or proximity of human residences to the affected area, factors which were certainly considered in the study, were not mentioned in the report as further corroborating data.

Case 2. Tampa Bay (Florida) Source of information: J.B. Rose, J.H. Paul, M.R. McLaughlin, V. J. Harwood, S. Farrah, M. Tamplin, J. Lukasik, M. Flanery, P. Stanek and H. Greening. 2000. …

Summary of results and conclusions. Perhaps one of the most striking findings of this study is the extent to which wild animals dominate as a source of fecal coliform and E. coli isolates. Over the course of the study, wild animal isolates dominated each site according to ARA. Ribotyping results were consistent; in 74% of all samples (n=53) the majority of isolates were identified as nonhuman. However, all sites displayed some level of human fecal pollution according to the three methods used (ribotyping, ARA and enterovirus counts). The three different methods did not always coincide on their detection of the presence or absence of human contamination, however the data collected over the course of the study unambiguously documents the presence of human fecal sources.

Case 3. Vermillion River (Minnesota) Source of information: Sadowsky, M. 2004. …

Summary of results and conclusions. Identifications indicated that 14% of unknowns matched with geese, 12% with pigs, 12% with cats, 10% with cows, 9% with human, 9% with deer, 9% with sheep, and 9% with turkey. The remaining percentages (30%) then fall off to match with the other groups or remained unclassified. The conclusion was that geese, pigs, cats, cows, humans, deer, sheep, and turkeys were the dominant sources of fecal pollution in the watershed.

Case 4. Anacostia River (Maryland/District of Columbia) Source of information: Hagedorn, C., K. Porter, and A. H. Chapman. 2003. …

Summary of results and conclusions. The dominant sources over all 10 months of sampling were (using ARA) birds (31%), wildlife (25%), and humans (24%), followed by pets (20%). Livestock detections were essentially non-existent.

Case 5. Accotink Creek, Blacks Run, and Christians Creek (Virginia) Source of information: Hyer, K. E. and D. L. Moyer. 2003. …

Outcomes 1. Summary of results and conclusions. Overall, about 65% of isolates could be assigned to a source in this study. Of the remaining 35%, some had no match in the library (unknown) and others matched to multiple sources (transient). Classification was made to the species level with some exceptions (for example, some bird-origin feces could be classified to species, but others could only be classified to "avian" or "poultry"). The MST results were a combination of the expected and the unanticipated. Fecal-indicator sources in Accotink Creek, the urban setting, were affected by human and pet feces, as expected, but were also strongly influenced by waterfowl. Blacks Run fecal-indicator bacteria were a mixture of human, pet, and livestock sources, as expected. Fecal-indicator concentrations in Christians Creek had a larger human and pet component than expected (about 25% of isolates), compared with livestock and poultry (about 50%). A further unexpected finding in all three watersheds was that relative contributions from each major source were about the same during both base-flow and storm-flow periods, despite the expectation that different transport pathways would dramatically change relative contributions from different sources.

[199] Article: "Wildlife Waste Is Major Water Polluter, Studies Say." By David A. Fahrenthold. Washington Post, September 29, 2006. http://www.washingtonpost.com/...

In the Potomac and the Anacostia, for instance, more than half of the bacteria in the streams came from wild creatures. EPA documents show that similar problems were found in Maryland, where wildlife were more of a problem than humans and livestock combined in the Magothy River, and in Northern Virginia tributaries such as Accotink Creek, where geese were responsible for 24 percent of bacteria, as opposed to 20 percent attributable to people.

"Wildlife consistently came up as being . . . a major player," said Peter Gold, an environmental scientist for the EPA.

Case 6. Avalon Bay (California) Source of information: Boehm, A. B., Fuhrman, J. A., Mrše, R. D. and Grant, S. B. 2003. …

Summary of results and conclusions. FIB [fecal indicator bacteria] in Avalon Bay appear to be from multiple, primarily land-based, sources including bird droppings, contaminated subsurface water, leaking drains, and runoff from street wash-down activities. Multiple shoreline samples and two subsurface water samples tested positive for human-specific bacteria and enterovirus, suggesting that at least a portion of the FIB contamination is from human sewage.

Case 7. Holmans Creek (Virginia) Source of information: Noto, M., K. Hoover, E. Johnson, J. McDonough, E. Stevens, and B. A. Wiggins. 2000. …

Summary of results and conclusions. Human sources were dominant in five of eight sampling events, and at four of nine locations. In 53 of the 64 samples, the proportion of human was above the MDP, and human was the dominant source in 29 of the 64 samples. Cattle was the dominant source on three of eight sampling days, and at five of nine locations. The proportion of cattle was above the MDP Minimal Detectable Percentage] in 52 of 64 samples, and cattle was the dominant source in 26 of them. Poultry and geese fecal contributions were low throughout the sampling period. The conclusions were that humans and cattle are the dominant sources of fecal pollution in the watershed.

Case 8. Homosassa Springs (Florida) Source of information: Griffin, D. W., R. Stokes, J. B. Rose, and J. H. Paul III. 2000. …

Summary of results and conclusions. F+ specific RNA coliphage analysis indicated that fecal contamination at all sites that had F+ RNA coliphage was from animal sources (mammals and birds). These results suggest that animal (either indigenous or residents of HSSWP [Homosassa Springs State Wildlife Park]) and not human sources influenced microbial water quality in the area of Homosassa River covered by this study.

More than 1 million cubic miles of fresh water lies underground, stored in cracks and pores below the Earth's surface. The vast majority of the world's fresh water available for human use is ground water, which has 30 times the volume of the world's fresh surface waters. Many parts of the country rely heavily on ground water for important needs such as drinking water, irrigation, industry, and livestock.

Some ecological systems also depend on ground water. For example, many fish species depend on spring-fed waters for their habitat or spawning grounds. Springs occur when a body of ground water reaches the Earth's surface. By some estimates, ground water feeds about 40 percent of total national stream flow, and the percentage could be much higher in arid areas.

To protect public health, EPA sets federal health-based standards for drinking water for public water systems. Public water systems include community water systems— systems that supply drinking water to 25 or more of the same people year-round in their residences. Community water systems serve more than 286 million people, or about 95 percent† of the U.S. population.

Public water systems must test for regulated contaminants and treat the water, if needed, to meet the federal standards. Disinfection of drinking water effectively protects against the risk of waterborne diseases such as typhoid, cholera, and hepatitis. Filtration, required for most public water systems that use surface water, provides additional protection against microbial contaminants.

In 2007, 92 percent of community water system customers (262 million people) were served by facilities for which states reported no violations of EPA's health-based drinking water standards (see graphic). Approximately 24 million people in 2007 were served by systems for which states did report violations of these standards. A portion, but not all, of these people might have been exposed to contaminants in drinking water at levels above standards. Most of these violations involved rules addressing microbial contaminants or disinfection byproducts (chemicals that can form when disinfectants, such as chlorine, react with naturally occurring materials in water). The level of health risk associated with violations varies, depending partly on which contaminants were involved, the extent to which a standard was exceeded, the extent to which the distribution system was affected, and how long the violation lasted. Microbial violations, in particular, can be short term.

These data address drinking water from community water systems only. They do not address the quality of drinking water that people get from nonpublic supplies (such as private wells and untreated surface water sources), from public water systems serving transient populations (such as roadside rest stops and campgrounds), or from nonresidential users (such as some workplaces and schools).

† NOTE: This 95% figure for the portion of Americans served by community water systems appears to be in conflict with the 15% figure (in the forthcoming footnote) for the portion of Americans who "rely on privately owned household wells for their drinking water."

Page 8: "These measures are based on violations reported by states to the EPA Safe Drinking Water Information System. EPA is aware of inaccuracies and underreporting of some data in this system. We are working with the states to improve the quality of the data."

Lead in drinking water primarily results from corrosion from Pb pipes, Pb-based solder, or brass or bronze fixtures within a residence (Lee et al., 1989; Singley, 1994; Isaac et al., 1997). Very little Pb in drinking water comes from utility supplies. Experiments of Gulson et al. (1994) have confirmed this by using isotopic Pb analysis. Tap water analyses for a public school, apartments, and free standing houses also indicate that the indoor plumbing is a greater source of Pb in drinking water than the utility, even for residences and schools serviced by Pb-pipe water mains (Moir et al., 1996). Ratios of influent Pb concentration to tap concentrations in homes in four municipalities in Massachusetts ranged between 0.17 to 0.69, providing further confirmation that in-home Pb corrosion dominates the trace quantities of Pb in municipal water supplies (Isaac et al., 1997). The information in this section addresses Pb concentrations in water intended for human consumption only. However, such water comes from the natural environment, and concentrations of Pb found in natural systems are discussed in Chapter 7.

[207] Report: "Quality of Water from Domestic Wells in Principal Aquifers of the United States, 1991–2004." By Leslie A. DeSimone. U.S. Department of the Interior, U.S. Geological Survey, National Water-Quality Assessment Program, 2009. http://pubs.usgs.gov/sir/2008/5227/includes/sir2008-5227.pdf

As part of the National Water-Quality Assessment Program of the U.S. Geological Survey (USGS), water samples were collected during 1991–2004 from domestic wells (private wells used for household drinking water) for analysis of drinking-water contaminants, where contaminants are considered, as defined by the Safe Drinking Water Act, to be all substances in water. Physical properties and the concentrations of major ions, trace elements, nutrients, radon, and organic compounds (pesticides and volatile organic compounds) were measured in as many as 2,167 wells; fecal indicator bacteria and radionuclides also were measured in some wells. The wells were located within major hydrogeologic settings of 30 regionally extensive aquifers used for water supply in the United States. One sample was collected from each well prior to any in-home treatment. Concentrations were compared to water-quality benchmarks for human health, either U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Levels (MCLs) for public water supplies or USGS Health-Based Screening Levels (HBSLs).

No individual contaminant was present in concentrations greater than available health benchmarks in more than 8 percent of the sampled wells. Collectively, however, about 23 percent of wells had at least 1 contaminant present at concentrations greater than an MCL [Maximum Contaminant Level] or HBSL [Health-Based Screening Level], based on analysis of samples from 1,389 wells in which most contaminants were measured. Radon, nitrate, several trace elements, fluoride, gross alpha- and beta-particle radioactivity, and fecal indicator bacteria were found most frequently (in one or more percent of wells) at concentrations greater than benchmarks and, thus, are of potential concern for human health. Radon concentrations were greater than the lower of two proposed MCLs (300 picocuries per liter or pCi/L) in about 65 percent of the wells and greater than the higher proposed MCL (4,000 pCi/L) in about 4 percent of wells. Nitrate, arsenic, manganese, strontium, and gross alpha-particle radioactivity (uncorrected) each were present at levels greater than MCLs or HBSLs in samples from about 5 to 7 percent of the wells; boron, fluoride, uranium, and gross beta-particle radioactivity were present at levels greater than MCLs or HBSLs in about 1 to 2 percent of the wells. Total coliform and Escherichia coli bacteria were detected in about 34 and 8 percent, respectively, of sampled wells. Thus, with the exception of nitrate and fecal indicator bacteria, the contaminants that were present in the sampled wells most frequently at concentrations greater than human-health benchmarks were naturally occurring.

Anthropogenic [manmade] organic compounds were frequently detected at low concentrations … but were seldom present at concentrations greater than MCLs or HBSLs. The most frequently detected compounds included the pesticide atrazine, its degradate deethylatrazine, and the volatile organic compounds chloroform, methyl tert-butyl ether, perchloroethene, and dichlorofluoromethane. Only 7 of 168 organic compounds were present in samples at concentrations greater than MCLs or HBSLs, each in less than 1 percent of wells. These were diazinon, dibromochloroprane, dinoseb, dieldrin, ethylene dibromide, perchloroethene, and trichloroethene. Overall, concentrations of any organic compound greater than MCLs or HBSLs were present in 0.8 percent of wells, and concentrations of any organic compound greater than one-tenth of MCLs or HBSLs were present in about 3 percent of wells. …

Geographic patterns of occurrence among principal aquifers showed that several contaminants and properties may be of greater potential concern in certain locations or regions than nationally. For example, radon concentrations were greater than the proposed MCLs in 30 percent (higher proposed MCL) and 90 percent (lower proposed MCL) of wells in crystalline-rock aquifers located in the Northeast, the central and southern Appalachians, and Colorado. Nitrate was present at concentrations greater than the MCL more frequently in agricultural areas than in other land-use settings. Contaminant concentrations also were related to geochemical conditions. For example, uranium concentrations were correlated with concentrations of dissolved oxygen in addition to showing regional patterns of occurrence; relatively high iron and manganese concentrations occurred everywhere, but were inversely correlated with dissolved oxygen concentrations. …

More than 43 million people—about 15 percent of the population of the United States—rely on privately owned household wells for their drinking water (Hutson and others, 2004). The quality and safety of these water supplies, known as private or domestic wells, are not regulated under Federal or, in most cases, state law. Rather, individual homeowners are responsible for maintaining their domestic well systems and for any routine water-quality monitoring. The Safe Drinking Water Act (SDWA) governs the Federal regulation and monitoring of public water supplies. Although the SDWA does not include regulation of domestic wells, its approach to evaluating the suitability of drinking water for public supplies provides a useful approach for evaluating the quality of drinking water obtained from domestic wells. The SDWA defines terminology related to water supply and the process by which drinking-water standards, called Maximum Contaminant Levels (MCLs), are established to ensure safe levels of specific contaminants in public water systems. The SDWA defines a contaminant as "any physical, chemical, biological, or radiological substance or matter in water" (U.S. Senate, 2002), whether potentially harmful or not (see sidebar on page 3).

When the SDWA was passed in 1974, it mandated a national study of rural water systems, including domestic wells. In that study, which focused on indicator bacteria and inorganic contaminants, contaminant concentrations were found to be greater than health benchmarks, which included available MCLs, in more than 15 percent of the domestic wells in the United States (National Statistical Assessment of Rural Water Conditions, or NSA; U.S. Environmental Protection Agency, 1984). Studies of many geographic areas and contaminants since then have shown that a variety of contaminants can be present in domestic wells, although usually at concentrations that are unlikely to have adverse human-health effects.

A contaminant is defined by the SDWA as "any physical, chemical, biological, or radiological substance or matter in water" (U.S. Senate, 2002; 40 CFR 141.2). This broad definition of contaminant includes every substance that may be found dissolved or suspended in water—everything but the water molecule itself. Another term sometimes used to describe a substance in water is "water-quality constituent," which has a meaning similar to the SDWA definition of contaminant.

The presence of a contaminant in water does not necessarily mean that there is a human-health concern. Whether a particular contaminant in water is potentially harmful to human health depends on its toxicity and concentration in drinking water. In fact, many contaminants are beneficial at certain concentrations. For example, many naturally occurring inorganic contaminants, such as selenium, are required in small amounts for normal physiologic function, even though higher amounts may cause adverse health effects (Eaton and Klaassen, 2001). On the other hand, anthropogenic organic contaminants, such as pesticides, are not required by humans, but may or may not have adverse effects on humans, depending on concentrations, exposure, and toxicity. As a first step toward evaluating whether a particular contaminant may adversely affect human health, its concentration measured in water can be compared to a U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Level (MCL) or a U.S. Geological Survey (USGS) Health-Based Screening Level (HBSL). Concentrations greater than these water-quality benchmarks indicate the potential for health effects (see discussion in the section, "Water-Quality Benchmarks for Human Health").

HBSLs [Health-Based Screening Levels], are non-enforceable benchmark concentrations that can be used in screening-level assessments to evaluate water-quality data within the context of human health…. … HBSLs are equivalent to existing USEPA [U.S. Environmental Protection Agency] Lifetime Health Advisory and Cancer Risk Concentration values (when they exist), except for unregulated compounds for which more recent toxicity information has become available….

Water-quality benchmarks, including MCLs and HBSLs, were available for 154 of the 214 contaminants measured in this study.

About 60 percent of shallow wells tested in agricultural areas contained pesticide compounds. Approximately 1 percent of the shallow wells tested had concentrations of pesticides above levels considered safe for human health. …

The data in this report do not provide information about the condition of deeper aquifers, which are more likely to be used for public water supplies. These data only characterize the uppermost layers of shallow aquifers typically used by private wells.

[209] Book: Molecular Biology and Biotechnology: A Guide for Teachers, Third edition. By Helen Kreuzer and Adrianne Massey. ASM [American Society for Microbiology] Press, 2008. Page 540:

Many people are frightened by the use of synthetic chemicals on food crops because they have heard that these chemicals are "toxic" and "cancer causing," but are all synthetic chemicals more harmful than substances people readily ingest, like coffee and soft drinks? No (Table 37.2). For example, in a study to assess the toxicities of various compounds, half of the rats died when given 233 mg of caffeine per kg of body weight, but it took more than 10 times that amount of glyphosate (4,500 mg glyphosate/kg body weight), which is the active ingredient in the herbicide Roundup, to cause the same percentage of deaths as 233 mg of caffeine.

"Municipal Solid Waste (MSW)—more commonly known as trash or garbage—consists of everyday items we use and then throw away, such as product packaging, grass clippings, furniture, clothing, bottles, food scraps, newspapers, appliances, paint, and batteries. This comes from our homes, schools, hospitals, and businesses."

[211] Web page: "Glossary of Recycling & Solid Waste Terms, Abbreviations and Acronyms." Connecticut Department of Energy and Environmental Protection, November 18, 2009. http://www.ct.gov/...

"Municipal Solid Waste (MSW) – Solid waste from residential, commercial and industrial sources, excluding solid waste consisting of significant quantities of hazardous waste as defined in section 22a-115, land-clearing debris, demolition debris, biomedical waste, sewage sludge and scrap metal."

[212] Report: "Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2010." EPA, Office of Solid Waste and Emergency Response, December 2011. http://www.epa.gov/...

Page 2: "MSW [municipal solid waste] does not include industrial, hazardous, or construction waste."

[213] Report: "Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2010." EPA, Office of Solid Waste and Emergency Response, December 2011. http://www.epa.gov/...

[214] Report: "Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2010." EPA, Office of Solid Waste and Emergency Response, December 2011. http://www.epa.gov/...

Page 4: "We estimated residential waste (including waste from apartment houses) to be 55 to 65 percent of total MSW generation. Waste from commercial and institutional locations, such as businesses, schools, and hospitals amounted to 35 to 45 percent."

[215] Report: "Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2010." EPA, Office of Solid Waste and Emergency Response, December 2011. http://www.epa.gov/...

"In 2010, Americans generated about 250 million tons of trash and recycled and composted over 85 million tons of this material, equivalent to a 34.1 percent recycling rate (see Figure 1 and Figure 2). On average, we recycled and composted 1.51 pounds out of our individual waste generation of 4.43 pounds per person per day."

[216] Calculated with data from the report: "Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Tables and Figures for 2010." EPA, Office of Resource Conservation and Recovery, December 2011. http://www.epa.gov/...

Generation, Materials Recovery, Composting, Combustion, and Discards Of Municipal Solid Waste, 1960 to 2010 (In thousands of tons and percent of total generation) …

* Composting of yard trimmings, food scraps and other MSW [municipal solid waste] organic material. Does not include backyard composting.

** Includes combustion of MSW in mass burn or refuse-derived fuel form, and combustion with energy recovery of source separated materials in MSW (e.g., wood pallets and tire-derived fuel). 2010 includes 25,930 MSW, 520 wood, and 2,810 tires (1,000 tons)

† Discards after recovery minus combustion with energy recovery. Discards include combustion without energy recovery.

NOTE: An Excel file containing the data and calculations is available upon request.

[217] Paper: "Municipal Solid Waste Recycling Issues." By Lester B. Lave and others. Journal of Environmental Engineering, October 1999. Pages 944-949. http://msl1.mit.edu/...

Page 944: "The almost universal aversion to landfills comes from the history of city dumps that smelled, looked terrible, were infested with rats and other pests, and posed risks to health. Sanitary engineers responded by designing modern landfills that pose few of these problems. Modern landfills have a minimum odor nuisance, do not have pests, and pose few problems after they are closed. With rules mandating daily cover, clay and rubber liners, clay caps, and leachate collection systems, modern landfills are a tribute to sanitary engineering."

[218] Paper: "Comparative LCAs [Life Cycle Assessments] for Curbside Recycling Versus Either Landfilling or Incineration with Energy Recovery." By Jeffrey Morris. International Journal of Life Cycle Assessment, 2005. Pages 273-284. http://www.springerlink.com/content/m423181w2hh036n4/

Page 276: "[R]efuse deposited in a landfill with a LFG [landfill gas] collection system will anaerobically decompose over time, and … the LFG collection system captures methane and other volatile gases released during that decomposition process."

Estimated greenhouse gas offsets for energy generated from landfill gases collected at SLO's landfill in 2002 are shown as the negative portion of the Garbage Impacts stacked bar. These reductions in greenhouse gases that would otherwise have been generated at coal fired power plants to produce the energy generated by SLO's [San Luis Obispo County, Washington] collected landfill gas were substantial enough, given the greater than 75% capture efficiency assumed for the landfill's gas collection system, to more than offset the greenhouse effect of methane emissions from gases that escape the landfill's gas collection system and carbon dioxide emissions from diesel fuels consumed in collecting refuse, hauling it to the landfill, and compacting it in place at the landfill.

Fig. 10 shows the amount of greenhouse gas emissions prevented each month by curbside recycling in WA State's four regions. Here even the waste management systems for three of the regions show a reduction in greenhouse gas emissions for recycling. This is because, unlike SLO County, collected LFG is not used to generate energy but is simply flared. As a result the uncollected landfill methane has more global warming impact than the energy used to collect, process and market materials collected in each region's curbside recycling programs.

Modern landfills are well-engineered facilities that are located, designed, operated, and monitored to ensure compliance with federal regulations. Solid waste landfills must be designed to protect the environment from contaminants which may be present in the solid waste stream. The landfill siting plan—which prevents the siting of landfills in environmentally-sensitive areas—as well as on-site environmental monitoring systems—which monitor for any sign of groundwater contamination and for landfill gas—provide additional safeguards. In addition, many new landfills collect potentially harmful landfill gas emissions and convert the gas into energy. …

Municipal solid waste landfills (MSWLFs) receive household waste. MSWLFs can also receive non-hazardous sludge, industrial solid waste, and construction and demolition debris. All MSWLFs must comply with the federal regulations in 40 CFR Part 258 (Subtitle D of RCRA), or equivalent state regulations. Federal MSWLF standards include:

• Location restrictions—ensure that landfills are built in suitable geological areas away from faults, wetlands, flood plains, or other restricted areas.

• Composite liners requirements—include a flexible membrane (geomembrane) overlaying two feet of compacted clay soil lining the bottom and sides of the landfill, protect groundwater and the underlying soil from leachate releases.

• Leachate collection and removal systems—sit on top of the composite liner and removes leachate from the landfill for treatment and disposal.

• Operating practices—include compacting and covering waste frequently with several inches of soil help reduce odor; control litter, insects, and rodents; and protect public health.

• Groundwater monitoring requirements—requires testing groundwater wells to determine whether waste materials have escaped from the landfill.

• Closure and postclosure care requirements—include covering landfills and providing long-term care of closed landfills.

• Corrective action provisions—control and clean up landfill releases and achieves groundwater protection standards.

• Financial assurance—provides funding for environmental protection during and after landfill closure (i.e., closure and postclosure care).

Some materials may be banned from disposal in municipal solid waste landfills including common household items such as paints, cleaners/chemicals, motor oil, batteries, and pesticides. Leftover portions of these products are called household hazardous waste. These products, if mishandled, can be dangerous to your health and the environment. Many municipal landfills have a household hazardous waste drop-off station for these materials.

Page 23: "Except for spills and natural events, most land contamination is the result of historical activities that are no longer practiced."

A Class 3 landfill is a scientifically engineered facility built into or on the ground that is designed to hold and isolate waste from the environment. Federal and state regulations strictly govern the location, design, operation and closure of Class 3 landfills in order to protect human health and the environment.

Class 3 landfills are the most common places for waste disposal and are an important part of an integrated waste management system. …

The life of a landfill depends on the size of the facility, the disposal rate and the compaction rate. All Class 3 landfills are permitted by the S.C. Department of Health and Environmental Control to accept a specific amount (tons) of waste each year – this amount cannot be exceeded. As mentioned earlier, Class 3 landfill operators strive for the maximum compaction rate possible in order to save space. Given these considerations, the average life expectancy could be anywhere from 30 to 50 years. Class 3 landfills must be monitored for 30 years after closure.

"It is a common misperception that a landfill is closed when it stops receiving waste," said New York City Department of Sanitation (DSNY) engineer, Richard Napolitano, who managed the day-to-day operations of the closure of East Mound. Closing a landfill requires consideration of its future uses, making engineering design adjustments, and installing a multi-tiered final cover system, or cap, that connects to and safeguards the integrity of the other environmental systems.

NOTE: See pages 7-22 for examples of reused landfills along with before-and-after pictures.

[224] Article: "Once an Urban Landfill, Now a Rowing Paradise." By Juliet Macur. New York Times, May 7, 2012. http://www.nytimes.com/...

Near the junction of the New Jersey Turnpike and Interstate 80, not far from the conga line of traffic grinding toward New York City, lies a body of water that was once a garbage dump.

It was a murky soup of reeking refuse, home to a flotilla of plastic bottles, tires and even refrigerators. The land around it was good for only two things, some longtime residents say, and that was illegal dumping and trapping muskrat.

But after a recent renaissance, that body of water, Overpeck Creek, and the new park abutting it have become a destination for a much more refined hobby. The creek, nearly all 134 acres of it in the upper region of the Meadowlands, has become the newest hot spot for rowing in the New York metropolitan area.

Superfund is the federal program to clean up the nation's abandoned hazardous waste sites. The program was created by law in 1980 in the wake of the discovery of toxic waste dumps such as Love Canal and Times Beach. It allows EPA to clean up sites and to compel those responsible for contamination to perform cleanups or reimburse the government for cleanups. Since Superfund's creation, remedies have been completed at 1,060 sites, and work is underway at an additional 423 sites. EPA has also identified and assessed thousands of sites. …

Reuse refers to the productive use of a site after cleanup. Over the past ten years, EPA has identified several types of reuse options. Communities have reused sites for industrial and commercial uses, such as factories and shopping malls. Sites have been used for housing and public works facilities, such as transit stations. Many communities have created new recreational amenities, like ball fields, parks and golf courses. Sites have also been reused to support ecological resources, including wildlife preserves and wetlands, as well as agricultural land.

NOTE: See pages 4 and 6 for examples of reused landfills along with before-and-after pictures.

Page 1: "Fresh Kills Landfill is located on the western shore of Staten Island. Approximately half the 2,200-acre landfill is composed of four mounds, or sections, identified as 1/9, 2/8, 3/4 and 6/7 which range in height from 90 feet to approximately 225 feet. These mounds are the result of more than 50 years of landfilling, primarily household waste."

Page 2: "Fresh Kills Landfill received its last barge of garbage on March 22, 2001, marking the beginning of a new era for the landfill."†

Page 3: "The city's five boroughs [are] Staten Island, Brooklyn, Manhattan, Queens and the Bronx…."

Page 6: "After the Second World War, population began to grow slowly. However, the central western shoreline of Staten Island remained rural. This would become the site for Fresh Kills Landfill, occupying nearly 3,000 acres. It started receiving waste in 1948 and this program was greatly accelerated in 1951."

NOTE: † This was supposed to be the last barge, but the remains of the World Trade Center were later interred at this site.

As development of Schmul Park and the Owl Hollow Fields wraps up at the perimeter of Freshkills Park, the largest recently-completed construction project on site might not be as noticeable. But that massive, grassy hill along the site's eastern border is no natural wonder; it is the product of a five-year-long closure process that concluded in November 2011. …

The 305-acre East Mound of Fresh Kills Landfill, the second largest of the four mounds with approximately 32 million tons of waste enclosed within, will ultimately become the East Park section of Freshkills Park.

b) Paper: "Estimating Method and Use of Landfill Settlement." By Michael L. Leonard and Kenneth J. Floom. American Society of Civil Engineers, Proceedings of Sessions of Geo‐Denver, 2000. http://www.scs-secure.com/...

Pages 3-4: "Table 1 - Landfill Densities … Long-Term Density [metric tons/m³ (lb/yd³)] … Landfilling … Defined as weight of refuse divided by total air space consumed by refuse, cover soil and other operations soil."

c) Report: "Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2010." EPA, Office of Solid Waste and Emergency Response, December 2011. http://www.epa.gov/...

Page 10: "The net per capita discard rate (after recycling, composting, and combustion for energy recovery) was 2.40 pounds per person per day, lower than the 2.51 per capita rate in 1960, when virtually no recycling occurred in the United States (see Table 4)."

d) Web page: "State & County QuickFacts: USA." U.S. Census Bureau, January 17, 2012.

- Credit for providing the idea and an outline to perform these calculations belongs to Bjørn Lomborg (Book: The Skeptical Environmentalist: Measuring the Real State of the World. Cambridge University Press, 2001. Pages 206-208.)

a) Report: "Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Tables and Figures for 2010." EPA, Office of Resource Conservation and Recovery, December 2011. http://www.epa.gov/...

Table 29: "Generation, Materials Recovery, Composting, Combustion, and Discards Of Municipal Solid Waste, 1960 to 2010 (In thousands of tons and percent of total generation)"

b) Report: "Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2010." EPA, Office of Solid Waste and Emergency Response, December 2011. http://www.epa.gov/...

Page 1: "In 2010, Americans generated about 250 million tons of trash … [or] 4.43 pounds per person per day."

NOTE: An Excel file containing the data and calculations is available upon request.

[230] Report: "Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2010." EPA, Office of Solid Waste and Emergency Response, December 2011. http://www.epa.gov/...

Page 6: "We recycled more than 62 percent of the paper and paperboard we generated. Over 19 million tons of yard trimmings were composted, representing almost a five-fold increase since 1990."

23 percent of wood packaging, mostly wood pallets, was recovered. Over 13 percent of plastic containers and packaging was recycled, mostly from soft drink, milk, and water bottles. Plastic bottles were the most recycled plastic products. Polyethylene terephthalate (PET) bottles and jars were recovered at about 29 percent. Recovery of high density polyethylene (HDPE) natural (white translucent) bottles was estimated at about 28 percent….

Overall recovery of nondurable goods was just over 36 percent in 2010. Nondurable goods generally last less than three years. Newspapers/mechanical papers and other paper products were the most recycled nondurable goods. Newspapers/mechanical papers include newspapers, directories, inserts, and some advertisement and direct mail printing. About 72 percent of newspapers/mechanical papers were recovered. Collectively, the recovery of other paper products such as office paper and magazines was 45 percent in 2010.

Produced by grinding wood mechanically; used for example in newsprint, and combined with larger proportions of chemical wood pulp for other qualities.

[232] Paper: "Municipal Solid Waste Recycling Issues." By Lester B. Lave and others. Journal of Environmental Engineering, October 1999. Pages 944-949. http://msl1.mit.edu/...

Page 946: "Separate collection of recyclables is particularly expensive, because each residence is visited twice (Lave et al. 1994). A collection truck that can carry regular MSW [municipal solid waste] and recyclables is preferable, because each residence gets a single pickup. … Because the truck will be collecting trash and recyclables in different compartments, one compartment will fill first requiring the truck to go to the recycling site and landfill even though the other compartment(s) is partially empty."

Page 947: "A full analysis of the environmental effects would also include the environmental effects associated with collection, sorting, and processing of recycled materials. These processes require capital equipment (particularly trucks) and the use of energy (for truck operation and sorting)."

[233] Paper: "Comparative LCAs [Life Cycle Assessments] for Curbside Recycling Versus Either Landfilling or Incineration with Energy Recovery." By Jeffrey Morris. International Journal of Life Cycle Assessment, 2005. Pages 273-284. http://www.springerlink.com/content/m423181w2hh036n4/

Page 273: "[A]dditional energy and environmental burdens [are] imposed by curbside collection trucks, recycled material processing facilities, and transportation of processed recyclables to end-use markets."

Page 275: "Fig. 1 also shows estimated energy used in 2002 for … manufacturing processed recyclables into new products."

Used glass must be sorted by color and cleaned before it can be crushed into cullet that is suitable for recycling into new containers. That contributes to much of the cost of recycling glass, said Joe Cattaneo, president of the Glass Packaging Institute in Alexandria, Va.

"It's not just a glass company buying it from your municipal waste company, or recycling company," Cattaneo said. "Some entity has to clean it so it meets the specifications of mixing it with sand, soda ash and limestone."

Another cost is transportation. The farther away a community is from glass processors and container manufacturers, he said, the more expensive it is to recycle it.

Collecting a ton of recyclable items is three times more expensive than collecting a ton of garbage because the crews pick up less material at each stop. For every ton of glass, plastic and metal that the truck delivers to a private recycler, the city currently spends $200 more than it would spend to bury the material in a landfill. …

The recycling program has been costing $50 million to $100 million annually, and that's just the money coming directly out of the municipal budget. There's also the labor involved: the garbage-sorting that millions of New Yorkers do at home every week. How much would the city have to spend if it couldn't rely on forced labor? …

I tried to estimate the value of New Yorkers' garbage-sorting by financing an experiment by a neutral observer (a Columbia University student with no strong feelings about recycling). He kept a record of the work he did during one week complying with New York's recycling laws. It took him eight minutes during the week to sort, rinse and deliver four pounds of cans and bottles to the basement of his building. If the city paid for that work at a typical janitorial wage ($12 per hour), it would pay $792 in home labor costs for each ton of cans and bottles collected. And what about the extra space occupied by that recycling receptacle in the kitchen? It must take up at least a square foot, which in New York costs at least $4 a week to rent. If the city had to pay for this space, the cost per ton of recyclables would be about $2,000.

… Less virgin pulp means less pollution at paper mills in timber country, but recycling operations create pollution in areas where more people are affected: fumes and noise from collection trucks, solid waste and sludge from the mills that remove ink and turn the paper into pulp.

[236] Paper: "Municipal Solid Waste Recycling Issues." By Lester B. Lave and others. Journal of Environmental Engineering, October 1999. Pages 944-949. http://msl1.mit.edu/...

Page 944: "In particular, recycling is a good policy only if environmental impacts and the resources used to collect, sort, and recycle a material are less than the environmental impacts and resources needed to provide equivalent virgin material plus the resources needed to dispose of the postconsumer material safely."

[237] Paper: "Comparative LCAs [Life Cycle Assessments] for Curbside Recycling Versus Either Landfilling or Incineration with Energy Recovery." By Jeffrey Morris. International Journal of Life Cycle Assessment, 2005. Pages 273-284. http://www.springerlink.com/content/m423181w2hh036n4/

Page 275: "Fig. 1 also shows estimated energy used in 2002 for operating the landfill…."

Page 277: "[There are] emissions from diesel fuels consumed in collecting refuse, hauling it to the landfill, and compacting it in place at the landfill."

[238] Report: "Facing America's Trash: What Next for Municipal Solid Waste?" U.S. Congress, Office of Technology Assessment, October 1989. http://www.fas.org/ota/reports/8915.pdf

Page 191: "In the mid-1970s, EPA concluded that recycling of waste materials generally resulted in less pollution than did manufacturing from virgin materials (251). [U.S. Environmental Protection Agency, Office of Solid Waste Management Programs, First Report to Congress, Resource Recovery and Source Reduction, Report SW-1 18, 3rd ed. (Washington, DC: 1974).]"

NOTE: Credit for bringing this report to attention belongs to Daniel K. Benjamin (Report: "Recycling Myths Revisited." Property and Environment Research Center, 2010. http://www.perc.org/files/ps47.pdf)

[239] Report: "Facing America's Trash: What Next for Municipal Solid Waste?" U.S. Congress, Office of Technology Assessment, October 1989. http://www.fas.org/ota/reports/8915.pdf

Proponents of recycling have made many claims about the relative levels of pollution generated by primary and secondary manufacturing processes, often arguing that recycling reduces pollution. In general, recycling may result in fewer pollutants when the entire MSW [municipal solid waste] system is considered. In particular, if recycled products replace products made from virgin materials, potential pollution savings may result from the dual avoidance of pollution from manufacturing and from subsequent disposal of replacement products made from virgin materials.

However, it is usually not clear whether secondary manufacturing produces less pollution per ton of material processed than primary manufacturing. Such an analysis, which is beyond the scope of this report, would have to examine all the pollutants produced during each step in production, as well as pollution generated while providing energy to the process itself and for transporting materials. It would also be necessary to account for the effects of water and raw materials use on ecological systems. Definitive research has not been conducted, however, on all the relevant primary and secondary materials processes. To provide a starting point, this section reviews some comparisons of manufacturing using recycled versus virgin materials. Box 5-G briefly illustrates some of the pollutants generated in secondary manufacturing processes.

Numerous publications have documented pollutants emitted from manufacturing processes that use virgin materials (e.g., 131). In the mid-1970s, EPA concluded that recycling of waste materials generally resulted in less pollution than did manufacturing from virgin materials (251). [U.S. Environmental Protection Agency, Office of Solid Waste Management Programs, First Report to Congress, Resource Recovery and Source Reduction, Report SW-1 18, 3rd ed. (Washington, DC: 1974).]

This generalization does not necessarily hold true in all cases. Using EPA data on paper production processes, for example, one researcher found no clear difference in measurements of chemical and biological oxygen demand and of total suspended solids in water effluents from recycling and virgin materials processes (262). The EPA data also indicated that 5 toxic substances "of concern" were found only in virgin processes and 8 were found only in recycling processes; of 12 pollutants found in both processes, 11 were present in higher levels in the recycling processes.

This researcher also noted that EPA's analyses of pollutants from virgin materials processing did not account for pollution from mining, timbering, and transportation (262). He concluded that "there are clear materials and energy conservation benefits to recycling, [but] the picture regarding environmental benefits and risks is complex, especially when specific hazardous pollutants are taken into account."

Virgin pulp processes generate various liquid and gas residues, depending on the type of paper, type of pulping process, and extent of bleaching (131). In general, large amounts of mill effluent are generated and this contains suspended solids, dissolved organic solids, various chemicals, and high BOD. Wastewater generated in the bleaching stage can contain dioxins, chlorine dioxide, hypochlorite, and other bleaching chemicals and byproducts. Spent liquor generated in the pulping process can contain a wide variety of chemicals; the liquors often are burned in a recovery furnace or fluidized bed. Other byproducts from the virgin paper process also can be used to generate energy. Gas emissions include chlorine, chlorine dioxide, sulfur dioxide, particulate, and hydrogen sulfide. Metals from de-inking are present in sludge residues; the concentration of lead in these sludges appears to be in the same range as in sludges from mills that use secondary fibers (64).

At primary aluminum smelters, one major concern is with the 'potliners'—pots lined with carbon that serves as the cathode and that contain compounds of aluminum, fluorine, and sodium. The potliners are replaced every 4 or 5 years, and disagreement has arisen over whether used potliners should be listed as a hazardous waste under RCRA [Resource Conservation and Recovery Act]. As of August 1988, EPA has been required to list potliners as hazardous waste. The aluminum industry claims, however, that potliners can be used to fire cement kilns, among other things, and therefore should not be considered a "waste. The designation of potliners as hazardous waste discourages this recycling. Most aluminum smelters in 1989 are disposing of spent potliners in hazardous waste landfills.

Various residues are generated during the steps necessary to produce steel (e.g., coking, sintering, ironmaking, steelmaking, rolling, and finishing steps) (131). Air emissions from coke ovens, for example, contain particulate and sulfur dioxide. Wastewater from steelmaking contains suspended and dissolved solids, oxygen-demanding substances, oil, phenols, and ammonia. Solid waste residues also are common, particularly from open hearth and oxygen furnaces. One study (131) modeled production processes and estimated that using less scrap and more ore would result in increased generation of phenols, ammonia, oxygen-demanding substances, sulfur dioxide, and particulate, and decreased generation of suspended solids.

Once a resin is produced, the environmental risks associated with fabricating products from the resins are the same whether the resin is produced from virgin or secondary materials. However, primary production processes generate air emissions, wastewater, and solid waste. The types and amounts of these wastes vary with different processes and types of plastics, and some are managed as hazardous waste. According to one analysis, five of the six chemicals whose production generates the most hazardous waste in the United States are chemicals commonly used by the plastics industry (268).

In general, air emissions are highest during the initial processing and recovery steps for monomers, solvents, catalysts, and additives. Wastewater associated with the primary production process can contain suspended monomers, co-monomers, polymers, additives, filler particulate, soluble constituents, and solvents that are washed or leached from the plastic. Solid waste is produced at various points, mostly from spillage, routine cleaning, particulate collection (from feeding, handling, grinding, and trimming processes), but also from production errors and a few production process byproducts. It can contain mostly polymers and small quantities of plasticizers, fillers, and other additives.

Some emissions are associated with the reprocessing of secondary plastic materials. For example, volatile air emissions can be generated during the heating of plastics, and residues can be contained in the rinse water used to cool the remelted resins.

Box 5-G-Pollutants Generated in Secondary Manufacturing Processes [Recycling]

Iron and Steel Recycling—Solid wastes produced by iron and steel foundries that primarily use ferrous scrap can contain lead, cadmium, and chromium; these wastes may be classified as hazardous (181). Sludges from core-making processes and baghouse dusts also are hazardous in some cases, depending on emission controls and the quality of incoming metal. Oman (181) cited one study indicating that 9 out of 21 foundries generated emission control residuals which would be considered as a hazardous waste on the basis of EP toxicity for lead. Air emissions also are common. Electric arc furnaces, which normally operate on 100 percent scrap, avoid some air emission problems because they do not use coke oven gases as a heat source; however, they can emit high levels of particulate if they use scrap with high concentrations of dirt, organic matter, and alloys (131).

Aluminum Recycling—When aluminum scrap is melted, associated substances (e.g., painted labels, plastic, and oil and grease) are burned off. The resulting air emissions can contain particulate matter in the form of metallic chlorides and oxides, as well as acid gases and chlorine gas (261). Similar types of emissions are likely from plants that smelt other scrap metals.

Paper Recycling—Printing inks often contain pigments that contain heavy metals such as lead and cadmium (261 ). These and other metals can be present in wastewater and de-inking sludge from paper recycling; for example, de-inking sludges have been reported with lead concentrations ranging from 3 to 294 ppm (dry weight) (64).

Materials Recycling Facilities (MRFs)—Very little testing has been conducted at MRFs to determine levels of pollutants. Even the results of testing that has been done at one facility that handles sorted paper, glass, and metals are ambiguous. At that facility, air withdrawn from within the building (i.e., prior to emissions controls) exhibited relatively low emission rates (in terms of pounds per hour) for cadmium, chromium, lead, mercury, and nickel (117, 262). However, actual concentrations of the metals in the emissions were high. No data were available about emissions after air pollution controls or on heavy metal concentrations in dust that settled in or around the plant.

Comporting—Concentrations of heavy metals tend to be higher in compost from mixed MSW comporting facilities than from compost made from separately collected organic wastes, primarily because mechanical separation cannot remove all metals. Compost from MSW that is co-composted with sewage sludge also tends to have high metal concentrations. Sewage treatment processes remove metals from effluent and concentrate them in sludge, and this emphasizes the role industrial pretreatment programs can play in reducing the metals entering treatment plants (240). The concentrations of metals in mixed MSW compost and co-compost samples vary from site to site (161). In some cases, zinc and lead exceeded State limits (26), while in other cases lead levels were lower than the limits. Problems also have been noted with heavy metals in mixed MSW compost in Europe (23, 92, 101, 115, 132, 149, 156). In one West German study, average concentrations of seven heavy metals were almost always lower in compost made from source-separated organic waste; in some cases they were essentially the same as soil concentrations (77, 78). More research is needed on the composition of leachate from compost products under different conditions.

Dioxins—Dioxins can be produced at paper mills, as a byproduct of pulp bleaching, and can be present in the effluent or sludge (241). Limited testing by EPA has shown that concentrations of 2,3,7,8-TCDD in sludges from two mills that use waste paper are relatively low, ranging from 2 to 37 parts per trillion (17).

Dioxins also have been detected in post-pollution control emissions from certain secondary metals smelting facilities. For example, dioxins have been reported in post-control emissions from (127):

• scrap wire reclamation (combustion to remove wire insulation, with afterburner);¹ and

Paper—Inks that need to be removed during recycling also contain acrylics, plastics, resins, varnishes, defoamers, and alcohols, some of which are discharged in wastewater. Paper recycling processes, particularly those with a bleaching step involving chlorine, also are known to discharge effluents that contain various chlorine-based compounds, including carbon tetrachloride, dichloroethane, methylene chloride, and trichloroethylene (261). In addition, the dispersing agents used in the de-inking processes (e.g., detergents and emulsifiers) end up in the sludge.

Plastics—Residues from the recycling of plastics are difficult to assess without knowing the specific details of proprietary systems used to wash materials and remove contaminants. Wash water and air emissions may be contaminated by residues from other products associated with recycled plastic, such as food or pesticides. At least one PET reclamation system planned to operate at a scale of 25,000 tons per year by 1990 will use 1,1,1-trichloroethane to remove residues. This toxic solvent is a well-known groundwater contaminant (239). However, according to Dow, the developer of the technology, the solvent is used in a closed system that will not result in release to the environment (165).

Compost—Few data are available on organic chemicals in compost. Compost from the Delaware facility has been found to contain PCBs in concentrations up to 5 parts per million (42), which is below the allowable limit of 10 parts per million set in Delaware's regulations. Questions have been raised about chemicals in grass clippings, particularly nitrogen from fertilizers and organic chemicals from pesticides (228). Many of these chemicals are insoluble and may bind to particles instead of being leached into groundwater, but there is little data to evaluate this. It also is unclear whether they could be taken up in food crops grown on compost containing the chemicals (228).

Chlorine and sulfur are common components in many products and chlorine is used in some recycling processes, so it is not surprising that both elements are found in residues at recycling facilities. For example, Visalli (262) calculated that uncontrolled emissions from one secondary aluminum smelter contained 1.7 pounds of hydrogen chloride and 1.8 pounds of S02 per hour.

¹ It is likely that dioxins and furans are produced from burning plastic wire coating. Wire scrap makes up a small percentage of total metal scrap processed.

[240] Paper: "Municipal Solid Waste Recycling Issues." By Lester B. Lave and others. Journal of Environmental Engineering, October 1999. Pages 944-949. http://msl1.mit.edu/...

From a review of the existing economic experience with recycling and an analysis of the environmental benefits (including estimation of external social costs), we find that, for most communities, curbside recycling is only justifiable for some postconsumer waste, such as aluminum and other metals. …

Similar to Haith (1998), we emphasize that some recycling improves environmental quality and sustainability, whereas other recycling has the opposite effect.

Table 2 gives a direct indication of the environmental benefits of avoided production due to recycling of different commodities. This table summarizes electricity use, fuel use, energy (including electricity and fuels), industrial water intake, some conventional pollutant emissions, global warming potential, toxic air releases, and hazardous waste generation for 1,000 metric tons of different commodity productions. … These calculations show an upper bound on savings from recycling by avoiding this primary production; the figures are an upper bound because the resource costs of recycling are not included.

The final row in Table 2 represents a rough estimate of the external environmental costs of this production. … Included in these costs are the estimated health effects related to ozone, particulate, and other conventional or "criteria pollutants." The estimates are reported in thousands of social cost dollars, and so a metric ton of primary aluminum is estimated to have an external environmental cost due to air emissions of $220 (Table 2). Comparing this number to the estimated cost of collection ($142/ton), aluminum appears to be a good candidate for recycling, even without counting the economic costs of producing a ton of aluminum.

Page 948: "Curbside recycling of postconsumer metals can save money and improve environmental quality if the collection, sorting, and recovery processes are efficient. Curbside collection of glass and paper is unlikely to help the environment and sustainability save in special circumstances."

[241] Paper: "Comparative LCAs [Life Cycle Assessments] for Curbside Recycling Versus Either Landfilling or Incineration with Energy Recovery." By Jeffrey Morris. International Journal of Life Cycle Assessment, 2005. Pages 273-284. http://www.springerlink.com/content/m423181w2hh036n4/

Recycling of newspaper, cardboard, mixed paper, glass bottles and jars, aluminum cans, tin-plated steel cans, plastic bottles, and other conventionally recoverable materials found in household and business municipal solid wastes consumes less energy and imposes lower environmental burdens than disposal of solid waste materials via landfilling or incineration, even after accounting for energy that may be recovered from waste materials at either type disposal facility. This result holds for a variety of environmental impacts, including global warming, acidification, eutrophication, disability adjusted life year (DALY) losses from emission of criteria air pollutants, human toxicity and ecological toxicity. The basic reason for this conclusion is that energy conservation and pollution prevention engendered by using recycled rather than virgin materials as feedstocks for manufacturing new products tends to be an order of magnitude greater than the additional energy and environmental burdens imposed by curbside collection trucks, recycled material processing facilities, and transportation of processed recyclables to end-use markets.

Results from the two studies described in this article show that recycling has substantial benefits compared with disposal in terms of reducing energy consumption and environmental burdens imposed by methods used for managing solid wastes. Specifically, recycling compared with disposal reduces potential impacts of solid waste management activities on all public health and environmental impact categories examined – global warming, acidification, eutrophication, human health effects from criteria air pollutants, human toxicity, and ecological toxicity. This conclusion holds regardless of whether disposal is via landfill without LFG [landfill gas] collection, landfill with LFG collection and flaring, landfill with LFG collection and energy recovery, incineration without energy recovery, or WTE incineration. For several environmental impact categories the net environmental benefits of recycling are reduced by WTE incineration as compared with landfilling, but the conclusion remains the same – recycling is environmentally preferable to disposal by a substantial margin.

[242] Paper: "Municipal Solid Waste Recycling Issues." By Lester B. Lave and others. Journal of Environmental Engineering, October 1999. Pages 944-949. http://msl1.mit.edu/...

Page 944: "MSW [municipal solid waste] recycling has been found to be costly for most municipalities compared to landfill disposal."

At one time, advocates claimed that recycling of MSW would be profitable for municipalities. Recycling programs were expected to more than pay for themselves. A few categories of postconsumer wastes can be recycled or reused profitably; aluminum cans and automobiles are common examples. … However, at current price levels, curbside collection programs for most recyclable materials cost more than landfilling and must be justified on environmental grounds. …

TABLE 1. Average Annual Curbside Recycling Costs in the United States … Net cost [compared to disposal] after sale of recyclables … Per household (dollars) [=] 21 … Per ton (dollars) [=] 97"

Page 947: "Recycling aluminum is generally profitable because of the high price for this scrap."

[243] Paper: "Comparative LCAs [Life Cycle Assessments] for Curbside Recycling Versus Either Landfilling or Incineration with Energy Recovery." By Jeffrey Morris. International Journal of Life Cycle Assessment, 2005. Pages 273-284. http://www.springerlink.com/content/m423181w2hh036n4/

Estimates of the economic value for recycling's pollution prevention and resource conservation benefits suggest that the societal value of these benefits outweighs the additional economic cost that is often incurred for waste management when systems for handling solid wastes add recycling trucks and processing facilities to their existing fleet of garbage collection vehicles and existing transfer and disposal facilities. This may be small recompense for the local waste management agency that is hard-pressed for cash to pay its waste management costs, especially in jurisdictions that have neither convenient methods for imposing quantity-based fees on waste generators – with those fees structured to cover the costs of recycling as well as garbage management programs – nor political support for doing the right thing environmentally.

However, ongoing developments in the trading of credits for emissions reductions, such as already exists for sulfur dioxide emissions through EPA's emissions permits trading program developed under the Clean Air Act and is under consideration through various experiments for greenhouse gases and other pollutants, do offer hope for the future. For example, a greenhouse gas credit of just $9 a ton would by itself offset the net costs of the average recycling program in the Urban West region of Washington State.

In northern Idaho, Kootenai County gave up collecting glass last year. In Oregon, which was the first of 11 states to adopt a bottle deposit law in 1971, Deschutes County stockpiled 1,000 tons of glass at its landfill before finally finding a use for it a couple years ago—as fill beneath an area for collecting compost.

Glass also has piled up at the landfill serving Albuquerque, N.M., where officials this year announced that a manufacturer of water-absorbing horticultural stones would eventually use up their stockpiles. New York City gave up glass recycling from 2002 to 2004 because officials decided it was too costly.

In a sense, glass ought to be the perfect commodity to recycle. It can be recycled an infinite number of times. Melting down one glass bottle and making another isn't particularly complicated or especially costly.

The challenge is that the main ingredient in glass, sand, is plentiful and cheap—often cheaper than cullet, which is glass that has been prepared for recycling.

[245] Article: "Report Calls Recycling Costlier Than Dumping." By Eric Lipton. New York Times, February 2, 2004. http://www.nytimes.com/...

Recycling metal, plastic, paper and glass in New York is more expensive than simply sending all the refuse to landfills and incinerators, even if city residents resume the habit of separating a sizable share of those kinds of waste, according to an analysis by the New York City Independent Budget Office that is set to be released today. …

Yet the Independent Budget Office's conclusion--that recycling cost the city about $35 million more in 2002 than conventional disposal would have--is so controversial that even before the new report was set to be released today, advocates of the recycling program condemned the analysis.

"State and city officials enacted laws mandating recycling and setting arbitrary goals even higher than the E.P.A.'s. Most states set rigid quotas, typically requiring that at least 40 percent of trash be recycled, often even more -- 50 percent in New York and California, 60 percent in New Jersey, 70 percent in Rhode Island."

"Starting in October, it will be against state law to throw plastic bottles in your trash."

[248] Policy Analysis: "Wasting Resources to Reduce Waste: Recycling in New Jersey." By Grant W. Schaumburg Jr. and Katherine T. Doyle. Cato Institute, January 26, 1994. http://www.cato.org/pubs/pas/pa202.pdf

The quantity of goods recycled as a result of New Jersey's Mandatory Recycling Act amounts to approximately 0.5million ton per year. …

Each of New Jersey's 21 counties is given some flexibility in its application of state mandates. Nine counties require municipalities to collect and market recyclables independently, six offer to market materials collected by the municipalities, and six coordinate both the collection and the marketing of recycled materials. All counties require households to recycle glass, aluminum, and newsprint. Some have also mandated the recycling of plastic beverage containers, all plastic containers, tin food containers, corrugated cardboard, grass clippings, junk mail, or magazines.[2] The commercial sector is required by all counties to recycle office paper and corrugated cardboard as well as the materials designated for household recycling.

To help finance the massive recycling effort, the Mandatory Recycling Act increased the tax on landfilled solid waste almost fourfold (from $0.12 per cubic yard to $1.50 per ton, or approximately $0.45 per cubic yard). The tax currently yields approximately $15 million annually for the State Recycling Fund, which is allocated as follows: 40 percent to municipalities and counties as tonnage grants; 35 percent for low-interest loans and loan guarantees to recycling businesses and industries and for research on collection, market stimulation, reuse techniques, and market studies; 10 percent for a public information and education campaign; 8 percent for county program grants; and 7 percent for state administrative costs.

[249] Article: "Few Towns Ready for Connecticut Recycling Law." By Nick Ravo. New York Times, January 22, 1991. http://www.nytimes.com/...

Three weeks past Connecticut's self-imposed deadline for its communities to begin mandatory recycling, most are still scrambling to start their programs. …

The law mandated that each of Connecticut's 169 towns and cities had until Jan. 1 to appoint a recycling coordinator and adopt a proper recycling ordinance.

Seattle is trying to boost recycling, already popular here, by making it mandatory. …

Banned from trash: For houses, apartments and condos, banned are cardboard, glass, plastic bottles, jars, aluminum and tin cans, all types of paper (unless soiled), and yard debris, which has been banned from residential garbage since 1989. For businesses, it's just paper, cardboard and yard debris.

The threshold: Trash cannot contain "significant amounts" of recyclables, which the city defines as more than 10 percent by volume, as determined by a garbage inspector.

[251] Article: "S.F. OKs toughest recycling law in U.S." By John Coté. San Francisco Chronicle, June 10, 2009. http://www.sfgate.com/...

"Throwing orange peels, coffee grounds and grease-stained pizza boxes in the trash will be against the law in San Francisco, and could even lead to a fine."

[252] Web page: "NYC Recycling Law." New York City Department of Sanitation. Accessed May 11, 2012 at http://www.nyc.gov/...

"This Law mandates recycling in NYC by residents, agencies, institutions, and businesses, including the designation of what materials are to be considered recyclable, the recovery of those materials, tonnages of recyclable materials that must be recycled annually, and responsibilities of each relevant party."

"Although there is not a statewide recycling law, many communities have passed their own recycling laws. Of the 351 Massachusetts communities, 168 of them have voluntarily adopted mandatory recycling ordinances, bylaws, or regulations. Most of these local requirements regulate single-family residences or those served by the municipal collection programs. A growing number of municipalities are also regulating multi-family properties and businesses."

Recycling has been mandatory in Monroe County for residents and businesses/institutions since 1992. …

The law states, in general, that residents must recycle the following food, drink and household product containers: steel, aluminum, glass bottles and jars (clear, green, and brown only), plastics (#s 1 and 2). …

According to law, residents must also recycle newspapers, magazines and corrugated cardboard.

China will ban shops from giving out free plastic bags and has called on consumers to use baskets and cloth sacks instead to reduce environmental pollution. …

The production, sale and use of ultra-thin plastic bags - those less than 0.025 millimeters, or 0.00098 inches, thick - were also banned, according to the State Council notice. Dated Dec. 31 and posted on a government Web site Tuesday, it called for "a return to cloth bags and shopping baskets."

"Ireland imposed a 15 cent tax (the equivalent of about 24 U. S. cents) on plastic shopping bags on March 4, 2002. Revenues from the tax are used for waste management, recycling, and other environmental initiatives."

San Francisco, California, and Westport, Connecticut have banned the distribution of plastic bags. Westport's ban will start in March 2009. …

The Seattle city council voted July 28, 2008 to approve a 20-cent "green fee" on disposable shopping bags that grocery, drug, and convenience stores provide to customers starting January 1, 2009. The proposal exempts bags used for (1) bulk items, such as fruit, vegetables, nuts, candy, or hardware; (2) potentially wet items, such as frozen foods, meat, flowers, and plants; (3) prepared foods or bakery goods; (4) prescription drugs; (5) laundry dry cleaning; and (6) newspapers. It also exempts bags sold in packages that are intended for garbage, pet waste, or yard waste disposal. Seattle estimates the fee would cause disposable bag use to decrease by 70% at stores required to impose the fee (50% overall) and that it will generate about $ 10 million annually.

[258] Article: "Nickel bag tax dissuades D.C. shoppers: Revenue shortfall $1.5 million." Associated Press, January 5, 2011. http://www.washingtontimes.com/...

District of Columbia shoppers have spent approximately $2 million on paper and plastic bags in the past year, one nickel at a time.

The city's 5-cent tax on bags began in January of last year, but consumers spent much less pocket change than predicted to pay for bags from grocery, liquor and convenience stores.

City officials had guessed the fee would raise $3.5 million to clean up the city's Anacostia River before the end of 2010. The tax brought in a total of $1.9 million in the first ten months of 2010, according to the city's latest data.

[259] Article: "Whole Foods sacks plastic bags." By Bruce Horovitz. USA Today, January 22, 2008 (updated). http://www.usatoday.com/...

Tuesday, Whole Foods (WFMI) will announce plans to stop offering disposable, plastic grocery bags in all 270 stores in the USA, Canada and United Kingdom by Earth Day — April 22. That means roughly 100 million plastic bags will be kept out of the environment between that date and the end of 2008, the company says.

"This is something our customers want us to do," says A.C. Gallo, Whole Foods co-president. "It's central to our core values of caring for communities and the environment."

Page 11: "Life Cycle Assessment (LCA) is a standard method for comparing the environmental impacts of providing, using and disposing of a product or providing a service throughout its life cycle (ISO 2006). In other words, LCA identifies the material and energy usage, emissions and waste flows of a product, process or service over its entire life cycle to determine its environmental performance."

This is the lightweight, plastic, carrier bag used in almost all UK supermarkets and often provided free of charge. It is a vest-shaped bag and has the advantage of being thin-gauged and lightweight. It has been termed "disposable" and "single use."

This type of lightweight, plastic, carrier bag is made from HDPE with a prodegradant additive that accelerates the degradation process. These polymers undergo accelerated oxidative degradation initiated by natural daylight, heat and/or mechanical stress, and embrittle in the environment and erode under the influence of weathering. The bag looks like the conventional HDPE bag being vest-shaped and thin-gauged.

These are thick-gauged or heavy duty plastic bags, commonly known as 'bags-for-life', and are available in most UK supermarkets. The initial bag must be purchased from the retailer but can be replaced free of charge when returned. The old bags are recycled by the retailer. {NOTE: LDPE bags are like the plastic bags used in mall clothing stores. The study (pages 80-81) found that LDPE bags have an average weight capacity of 19 kilograms, and standard disposable plastic (HDPE) bags have a capacity of 18.22 kilograms, which amounts to a difference of less than 5%.}

This type of bag is made from spunbonded non-woven polypropylene. The non-woven PP bag is stronger and more durable than a bag for life and is intended to be reused many times. To provide stability to the base of the bag, the bag comes with a semi-rigid insert.

This type of bag is woven from cotton, often calico, an unbleached cotton with less processing, and is designed to be reused many times.

These are generally no longer used in UK supermarkets, although they are available from other retail shops. The paper bag was in effect the first "disposable" carrier bag, but was superseded in the 1970s by plastic carrier bags which were seen as the perfect alternative, as they did not tear when wet.

Biopolymer carrier bags are a relatively recent development. They are only available in a few UK supermarkets. The biopolymers are usually composed of either polylactic acid (PLA), made from the polymerisation of lactic acids derived from plant-based starch, or starch polyester blends, which combine starch made from renewable sources such as corn, potato, tapioca or wheat with polyesters manufactured from hydrocarbons (Murphy et al 2008). These biodegradable polymers decompose to carbon dioxide, methane, water, inorganic compounds or biomass (Nolan-ITU 2003).

Pages 18-19: "The study is a 'cradle to grave' life cycle assessment. Therefore, the carrier bag systems investigated include all significant life cycle stages from raw material extraction, through manufacture, distribution use and reuse to the final management of the carrier bag as waste. … [T]he study quantifies all energy and materials used, traced back to the extraction of resources, and the emissions from each life cycle stage, including waste management."

Each type of carrier bag is designed for a different number of uses. Those intended to last longer need more resources in their production. To make the comparison fair, the environmental impacts of the carriers bags were considered in relation to carrying the same amount of shopping over a period based on studies of their volumes and the number of items consumers put into them. Resource use, primary and secondary reuse and end-of-life recovery play a pivotal role in the environmental performance of the carrier bags studied. The analysis showed that the environmental impacts of each type are significantly affected by the number of times a carrier is used.

Page 55: "All the reports agree that the extraction and production of raw materials has the greatest effect on the environmental performance of the carrier bags studied."

Page 57: "The manufacturing of the bags is normally the most significant stage of the life cycle, due to both the material and energy requirements. The impact of the energy used is often exacerbated by their manufacture in countries where the electricity is produced from coal-fired power stations."

The environmental impact of carrier bags is dominated by resource use and production. Transport, secondary packaging and end-of-life processing generally have a minimal influence on their environmental performance. …

Reusing lightweight [plastic] carrier bags as bin liners [trash bags] produces greater benefits than recycling bags due to the benefits of avoiding the production of the bin liners they replace.

What is it? This impact category refers to the depletion of non-living (abiotic) resources such as fossil fuels, minerals, clay and peat.

How is it measured? Abiotic depletion is measured in kilograms of Antimony (Sb) equivalents.

What is it? Global warming potential is a measure of how much of a given mass of a green house gas (for example, CO2, methane, nitrous oxide) is estimated to contribute to global warming. Global warming occurs due to an increase in the atmospheric concentration of greenhouse gases which changes the absorption of infra red radiation in the atmosphere, known as radiative forcing leading to changes in climatic patterns and higher global average temperatures.

How is it measured? Global warming potential is measured in terms of CO2 equivalents.

What is it? The formation of photochemical oxidant smog is the result of complex reactions between NOx and VOCs under the action of sunlight (UV radiation) which leads to the formation of ozone in the troposphere. The smog phenomenon is very dependent on meteorological conditions and the background concentrations of pollutants.

How is it measured? It is measured using photo-oxidant creation potential (POCP) which is normally expressed in ethylene equivalents.

What is it? This is caused by the addition of nutrients to a soil or water system which leads to an increase in biomass, damaging other lifeforms. Nitrogen and phosphorus are the two nutrients most implicated in eutrophication.

How is it measured? Eutrophication is measured in terms of phosphate (PO4 3-) equivalents.

What is it? This results from the deposition of acids which leads to a decrease in the pH, a decrease in the mineral content of soil and increased concentrations of potentially toxic elements in the soil solution. The major acidifying pollutants are SO2, NOx, HCL and NH3.

What is it? Toxicity is the degree to which something is able to produce illness or damage to an exposed organism. There are 4 different types of toxicity; human toxicity, terrestrial ecotoxicity, marine aquatic ecotoxicity and fresh water aquatic ecotoxicity.

How is it measured? Toxicity is measured in terms of dichlorobenzene equivalents.

A comparison of life cycle environmental impacts should be based on a comparable function (or ‘functional unit’) to allow a fair comparison of the results. The carrier bags studied are of different volumes, weights and qualities. The Environment Agency commissioned a survey¹¹ which found that, over a 4 weeks period, supermarket shoppers purchased an average of 446 items. The functional unit has therefore been defined as:

Carrying one month’s shopping (483 items) from the supermarket to the home in the UK in 2006/07.

Page 32: "All results and charts shown refer to the functional unit, i.e. the carrier bags required to carry one month's shopping (483 items) from the supermarket to the home in the UK in 2006/07."

Page 36: "Table 5.1 The environmental impact of the HDPE [standard disposable plastic] bag"

Page 43: "Table 5.6 The environmental impact of the non-woven PP [polypropylene] bag"

Page 44: "Table 5.9 The environmental impact of the cotton bag (used 173 times)"

Page 72: "Table A.4.1 The carrier bags included in the study with specification and major assumptions … Expected life … PP (polypropylene) fibre = 104 uses … Calico cotton = 52 uses"

NOTE: An Excel file containing the data and calculations is available upon request.

Page 36: "Table 5.1 The environmental impact of the HDPE [standard plastic] bag"

Page 59: "The HDPE prodegradant bag had a larger impact than the HDPE bag in all categories considered. Although the bags were very similar, the prodegradant bag weighed slightly more and therefore used more energy during production and distribution."