Pollution Terms
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Acid deposition, or acid rain as it is commonly known, occurs when emissions of sulfur dioxide (SO2) and oxides of nitrogen (NOx) react in the atmosphere with water, oxygen, and oxidants to form various acidic compounds. These compounds then fall to the earth in either dry form (such as gas and particles) or wet form (such as rain, snow, and fog). Acid rain causes acidification of lakes and streams and contributes to the damage of trees at high elevations (for example, red spruce trees above 2,000 feet) and many sensitive forest soils. In addition, acid rain accelerates the decay of building materials and paints, including irreplaceable buildings, statues, and sculptures that are part of our nation’s cultural heritage. Prior to falling to the earth, sulfur dioxide (SO2) and nitrogen oxide (NOx) gases and their particulate matter derivatives-sulfates and nitrates-contribute to visibility degradation and harm public health. Click here for more on acid rain effects.
Air Quality Index
The standard system that state and local air pollution control programs use to notify the public about levels of air pollution. The AQI tracks levels of two pollutants – ozone (smog) and particle pollution (tiny particles from ash, vehicle exhaust, soil dust, pollen, and other pollution).
Alternative fuels
Fuels that can replace ordinary gasoline. Alternative fuels may have particularly desirable energy efficiency and pollution reduction features. Alternative fuels include compressed natural gas, alcohols, liquefied petroleum gas (LPG), and electricity.
Asbestos has been used in building materials, paper products, plastics, and other products. Exposure mainly occurs in indoor air where it may be released from these materials. Effects on the lung are a major health concern from asbestos, as chronic (long-term) exposure to asbestos in humans via inhalation can result in a lung disease termed asbestosis. Asbestosis is characterized by shortness of breath and cough and may lead to severe impairment of respiratory function. Cancer is also a major concern from asbestos exposure, as inhalation exposure can cause lung cancer and mesothelioma (a rare cancer of the thin membranes lining the abdominal cavity and surrounding internal organs), and possibly gastrointestinal cancers in humans. EPA has classified asbestos as a Group A, known human carcinogen. For complete information on asbestos visit the EPA website
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Brownfields
Brownfields are real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant. Cleaning up and reinvesting in these properties takes development pressures off of undeveloped, open land, and both improves and protects the environment. For resources on general information, laws, grant and funding, visit the U.S. EPA website.
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Cap and trade is a market-based policy tool for environmental protection. A cap and trade program establishes an aggregate emission cap that specifies the maximum quantity of emissions authorized from sources included in the program. The regulating authority of a cap and trade program creates individual authorizations (”allowances”) to emit a specific quantity (e.g., 1 ton) of a pollutant. The total number of allowances equals the level of the cap. To be in compliance, each emission source must surrender allowances equal to its actual emissions. It may buy or sell (trade) them with other emissions sources or market participants. Each emission source can design its own compliance strategy – emission reductions and allowance purchases or sales – to minimize its compliance cost. EPA: PDF on How to Develop a Cap and Trade Program
Carbon monoxide (CO)
A colorless, odorless, poisonous gas, produced by incomplete burning of carbon-based fuels, including gasoline, oil, and wood. Carbon monoxide is also produced from incomplete combustion of many natural and synthetic products, including cigarette smoke. When carbon monoxide enters the body, it reacts with chemicals in the blood and prevents the blood from bringing oxygen to cells, tissues, and organs. The body needs oxygen for energy, so high-level exposures to carbon monoxide can cause serious health effects and even death. Symptoms of exposure to carbon monoxide can include vision problems, reduced alertness, and general reduction in mental and physical functions.
Sources of carbon monoxide include: unvented kerosene and gas space heaters; leaking chimneys and furnaces; back-drafting from furnaces, gas water heaters, wood stoves, and fireplaces; gas stoves; generators and other gasoline powered equipment; automobile exhaust from attached garages; and tobacco smoke. Incomplete oxidation during combustion in gas ranges and unvented gas or kerosene heaters may cause high concentrations of CO in indoor air. Worn or poorly adjusted and maintained combustion devices (e.g., boilers, furnaces) can be significant sources, or if the flue is improperly sized, blocked, disconnected, or is leaking. Auto, truck, or bus exhaust from attached garages, nearby roads, or parking areas can also be a source.
These chemicals and some related chemicals have been used in great quantities in industry, for refrigeration and air conditioning, and in consumer products. CFCs and their relatives, when released into the air, rise into the stratosphere, a layer of the atmosphere high above the Earth. In the stratosphere, CFCs and their relatives take part in chemical reactions which result in reduction of the stratospheric ozone layer, which protects the Earth’s surface from harmful effects of radiation from the sun. The 1990 Clean Air Act includes provisions for reducing releases (emissions) and eliminating production and use of these ozone-destroying chemicals.
Clean Air Act (CAA)
The original Clean Air Act was passed in 1963, but our national air pollution control program is actually based on the 1970 update. The 1990 Clean Air Act Amendments are the most far-reaching revisions of the 1970 law, which is also the 1990 Clean Air Act.
Clean fuels
Low-pollution fuels that can replace ordinary gasoline. These are alternative fuels, including gasohol (gasoline-alcohol mixtures), natural gas, and LPG (liquefied petroleum gas).
The Earth’s climate is predicted to change because human activities are altering the chemical composition of the atmosphere through the buildup of greenhouse gases-primarily carbon dioxide (CO2), methane (CH4), and nitrous oxide (NOx). The heat-trapping property of these gases is undisputed. Although uncertainty exists about exactly how Earth’s climate responds to these gases, global temperatures are rising. For more information about climate change.
Combustion
Another word for burning. Many important pollutants, such as sulfur dioxide, nitrogen oxides, and particulates (PM-10) are combustion products, often products of the burning of fuels such as coal, oil, gas, and wood.
Continuous emission monitoring systems (CEMS)
Machines which measure, on a continuous basis, pollutants released by a source. The 1990 Clean Air Act requires continuous emission monitoring systems for certain large sources.
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Emission:
Release of pollutants into the air from a source.
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Greenhouse Gas (GHG) Offsets
A greehouse gas (GHG) offset, sometimes referred to as a carbon offset, is a tradable commodity representing a unit of GHG emissions reduction or avoidance. Typically, a GHG offset represents a reduction or avoidance of one metric ton of carbon dioxide equivalent (CO2e). GHG offsets may be purchased by consumers and businesses to “offset” their own emissions, such as those associated with electricity consumption, product manufacturing processes, automobile use, and air travel. GHG offsets can be derived from a variety of project types that reduce or avoid GHG emissions, with diverse methods for measuring these reductions. Examples of GHG reduction projects include renewable electricity generation, energy efficiency measures, methane capture at landfill sites, soil carbon sequestration, and reforestation projects. Developers of these project types can sell GHG offsets to consumers or businesses to help finance their projects.
All of the GHG offset providers and products presented on the Green Power Network are available nationally and derived at least in part from U.S.-based renewable energy generation projects.
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Hazardous air pollutants (HAPs)
Toxic chemicals that cause serious health and environmental effects. Health effects include cancer, birth defects, nervous system problems, and death due to massive accidental releases. Hazardous air pollutants are released by sources such as chemical plants, dry cleaners, printing plants, and motor vehicles.
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Landfill Gas
Municipal solid waste contains significant portions of organic materials that produce a variety of gaseous products when dumped, compacted, and covered in landfills. Anaerobic bacteria thrives in the oxygen-free environment, resulting in the decomposition of the organic materials and the production of primarily carbon dioxide and methane. Carbon dioxide is likely to leach out of the landfill because it is soluble in water. Methane, on the other hand, which is less soluble in water and lighter than air, is likely to migrate out of the landfill. Landfill gas energy facilities capture the methane (the principal component of natural gas) and combust it for energy.
Because some materials have higher heat content than others, the amount of energy that can be produced by combusting MSW is a function of the composition of the waste stream. For example, certain types of plastics have more than three times the heat content of yard trimmings or organic textiles. In general, combustible non-biogenic materials are characterized by higher heat contents per unit weight than combustible biogenic materials. Thus, the ratio of biogenic to non-biogenic material volumes can have a considerable effect on the heat content of the waste stream.
Lead
Lead is a toxic metal that was used for many years in products found in and around our homes. Lead also can be emitted into the air from motor vehicles and industrial sources, and lead can enter drinking water from plumbing materials. Lead may cause a range of health effects, from behavioral problems and learning disabilities, to seizures and death. Children six years old and under are most at risk. Learn more about lead.
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Mercury is a naturally occurring element that is found in air, water, and soil. It exists in several forms: elemental or metallic mercury, inorganic mercury compounds, and organic mercury compounds.Human activities, such as burning coal and using mercury to manufacture certain products, have increased the amount of mercury in many parts of the environment including the atmosphere and in lakes and streams. People and animals are exposed to mercury by eating organisms that live in places where microbes have converted some of the natural and human mercury to a more toxic form, methylmercury.
Mobile sources
Motor vehicles and other moving objects that release pollution. Mobile sources are divided into two groups: road vehicles, which includes cars, trucks, and buses; and non-road vehicles, which includes trains, planes, and lawn mowers.
Municiple Solid Waste
The municipal solid waste industry has four components: recycling, composting, landfilling, and waste-to-energy via incineration. Municipal solid waste is total waste excluding industrial waste, agricultural waste, and sewage sludge. As defined by the U.S. Environmental Protection Agency, it includes durable goods, non-durable goods, containers and packaging, food wastes, yard wastes, and miscellaneous inorganic wastes from residential, commercial, institutional, and industrial sources. Examples from these categories include: appliances, newspapers, clothing, food scrapes, boxes, disposable tableware, office and classroom paper, wood pallets, rubber tires, and cafeteria wastes. Waste-to-energy combustion and landfill gas are byproducts of municipal solid waste.
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NAAQS
National ambient air quality standards. Ambient standards developed by EPA that must be attained and maintained to protect public health. NAAQS exist for specific matter, sulfur dioxide, nitrogen dioxide, ozone, carbon dioxide, and lead.
Nitrogen oxides, or NOx, is the generic term for a group of highly reactive gases, all of which contain nitrogen and oxygen in varying amounts (including nitrogen dioxide, nitric acid, nitrous oxide, nitrates, and nitric oxide).. Many of the nitrogen oxides are colorless and odorless. However, one common pollutant, nitrogen dioxide (NO2) along with particles in the air can often be seen as a reddish-brown layer over many urban areas. Nitrogen oxides form when fuel is burned at high temperatures, as in a combustion process. The primary sources of NOx are motor vehicles, electric utilities, and other industrial, commercial, and residential sources that burn fuels. The chief concerns associated with nitrogen oxides are its contribution to global warming and respiratory related health problems. For more information on nitrogen oxide view the EPA .PDF
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Ozone is a gas that occurs both in the Earth’s upper atmosphere and at ground level. Ozone can be “good” or “bad” for your health and the environment, depending on its location in the atmosphere. Ozone occurs in two layers of the atmosphere. The layer closest to the Earth’s surface is the troposphere. Here, ground-level or “bad” ozone is an air pollutant that is harmful to breathe and it damages crops, trees and other vegetation. It is a main ingredient of urban Smog.The troposphere generally extends to a level about 6 miles up, where it meets the second layer, the stratosphere. The stratosphere extends upward from about 6 to 30 miles. The stratospheric or “good” ozone protects life on Earth from the sun’s harmful ultraviolet (UV) rays. Learn more about ozone
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Particulates/ Particulate matter
Particulate matter includes dust, soot, and other tiny bits of solid materials that are released into and move around in the air. Particulates are produced by many sources, including burning of diesel fuels by trucks and buses, incineration of garbage, mixing and application of fertilizers and pesticides, road construction, industrial processes such as steel making, mining operations, agricultural burning (field and slash burning), and operation of fireplaces and wood stoves. Particulate pollution can cause eye, nose, and throat irritation and other health problems.
Pollutants (pollution)
Unwanted chemicals or other materials found in the air, water, and/or ground. Pollutants can harm health, the environment and property. Many air pollutants occur as gases or vapors, but some are very tiny solid particles: dust, smoke, or soot.
Smog: A mixture of pollutants, principally ground-level ozone, produced by chemical reactions in the air. A major portion of smog-formers comes from burning petroleum-based fuels such as gasoline, but also include volatile organic compounds that are found in products such as paints and solvents. Smog can harm health, damage the environment and cause poor visibility.
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Regional Haze/Particulate Matter
Regional haze is the “dirty-looking” air that prevents us from seeing clearly or very far through the air. It especially affects our enjoyment of national parks, such as the Grand Canyon and the Great Smoky Mountains. Sulfate particles, formed by the reaction of sulfur dioxide (SO2) from power plants and other sources in the atmosphere, account for 50 to 70 percent of the visibility reduction in the eastern part of the U.S. Both sulfate and nitrate particles (resulting from nitrogen oxides (NOx) emissions) affect visibility in the western U.S.
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Source
Any place or object from which pollutants are released. A source can be a power plant, factory, dry cleaning business, gas station, or a farm. Cars, trucks, and other motor vehicles are sources. Consumer products and machines used in industry can also be sources.
Smog is the brownish haze that pollutes our air, particularly over cities in the summer. Smog can make it difficult for some people to breathe and it greatly reduces how far we can see through the air. The primary component of smog is ozone, a gas that is created when nitrogen oxides (NOx) react with other chemicals in the atmosphere, especially in strong sunlight. NOx is produced whenever we burn something, such as coal in a power plant or gasoline in a car’s engine. Like sulfur dioxide (SO2), NOx can travel large distances before reacting to form ozone. For that reason, it creates regional pollution problems, rather than simply affecting the local area where it is emitted.
Stationary Source
A place or object from which pollutants are released which does not move. Stationary sources include power plants, gas stations, incinerators, and houses.
Sulfur dioxide, or SO2, belongs to the family of sulfur oxide gases (SOx). These gases dissolve easily in water. Sulfur is prevalent in all raw materials, including crude oil, coal, and ore that contains common metals like aluminum, copper, zinc, lead, and iron. SOx gases are formed when fuel containing sulfur, such as coal and oil, is burned, and when gasoline is extracted from oil, or metals are extracted from ore. SO2 dissolves in water vapor to form acid, and interacts with other gases and particles in the air to form sulfates and other products that can be harmful to people and their environment. Chief among concerns are:
SO2 contributes to respiratory illness, particularly in children and the elderly, and aggravates existing heart and lung diseases.
SO2contributes to the formation of acid rain, which:
- damages trees, crops, historic buildings, and monuments; and
- makes soils, lakes, and streams acidic.
SO2 contributes to the formation of atmospheric particles that cause visibility impairment, most noticeably in national parks.
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Ultraviolet B (UVB)
A type of sunlight. The ozone in the stratosphere filters out ultraviolet B rays and keeps them from reaching the Earth. Thinning of the ozone layer in the stratosphere results in increased amounts of ultraviolet B reaching the Earth. Ultraviolet B exposure has been associated with skin cancer, eye cataracts, and damage to the environment.
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Volatile organic compounds (VOCs)
Organic chemicals all contain the element carbon (C). Organic chemicals are the basic chemicals found in living things and in products derived from living things, such as coal, petroleum, and refined petroleum products. Many of the organic chemicals we use do not occur in nature, but were synthesized by chemists in laboratories. Volatile chemicals readily produce vapors at room temperature and normal atmospheric pressure. Vapors escape easily from volatile liquid chemicals. Volatile organic chemicals include gasoline, industrial chemicals.
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