Association of American Railroads

Ceiling

Microgram (1E-6 Grams)

Micrograms per Liter (Parts per billion in DI Water)

Micrograms per Cubic Meter

Angstrom (1E-10 meters)

Attainment Area (CAA)

Atomic Absorption: Refers to instrument for metals analysis.

Acceptable Ambient Concentration

Association of American Pesticide Control Officials, Inc.

Ambient Air Quality Standards (CAA)

Penetration of a substance into the body of another.

Asbestos Containing Building Materials

Actual Cubic Feet per Minute of gas or air flowing at existing temperature and pressure.

American Conference of Governmental & Industrial Hygienists

A hydrogen containing compound that reacts with water to produce hydrogen ions (H+) with a pH of less than 7.0.

Acid rain is a form of air pollution produced when acid chemicals are incorporated into rain, snow, fog or mist. The "acid" in acid rain comes from sulfur oxides and nitrogen oxides, products of burning coal and other fuels and from certain industrial processes. The sulfur oxides and nitrogen oxides are related to two strong acids: sulfuric acid and nitric acid. When sulfur dioxide and nitrogen oxides are released into the air and are blown into areas where the weather is et, the acids can fall to the Earth in the rain, snow, fog or mist. In areas where the weather is dry, the acid chemicals may become incorporated into dusts or smokes. Acid rain can damage the environment, human health and property.

Alternative Concentration Limit (40 CFR Part 403): General pretreatment regulations for existing and new sources of pollution (CWA).

Asbestos Containing Materials: Materials which contain greater than one percent asbestos.

American Chemical Society