Abatement: Reducing the degree or intensity of, or eliminating, pollution.

Adaptation: Changes in an organism's physiological structure or function or habits that allow it to survive in new surroundings.

Aerated Lagoon: A holding and/or treatment pond that speeds up the natural process of biological decomposition of organic waste by stimulating the growth and activity of bacteria that degrade organic waste.

Affected Landfill: Under the Clean Air Act, landfills that meet the criteria for capacity, age, and emissions set by the Environmental Protection Agency. They are required to collect and combust their gas emissions.

Agent: Any physical, chemical, or biological entity that can be harmful to an organism.

Air Quality Standards: The level of pollutants prescribed by regulations that are not to be exceeded during a given time in a defined area.

Alkalinity: The capacity of bases to neutralize acids. An example is lime added to lakes to decrease acidity.

Alternative Fuels: Substitutes for traditional liquid, oil-derived motor vehicle fuels like gasoline and diesel. Includes mixtures of alcohol-based furls with gasoline, methanol, ethanol, compressed natural gas, and others.

Aquifer: An underground geological formation, or group of formations, containing water. Are sources of groundwater for wells and springs.

Assimilation: The ability of a body of water to purify itself of pollutants.

ACScale Sound Level: A measurement of sound approximating the sensitivity of the human ear, used to note the intensity or annoyance level of sounds.

Bacteria: Microscopic living organisms that can aid in pollution control by metabolizing organic matter in sewage, oil spills or other pollutants. However, bacteria in soil, water of air can also cause human, animal and plant health problems.

Best Available Control Measures (BACM): A term used to refer to the most effective measures (according to EPA guidance) for controlling small or dispersed particulates and other emissions from sources such as roadway dust, soot and ash from woodstoves and open burning of rush, timber, grasslands, or trash.

Source: U.S. Environmental Protection Agency