ABSTRACT
Air pollution produced when acid chemicals are incorporated into rain, snow, fog, or mist. If the acid chemicals in the air are blown into areas where the weather is wet, the acids can fall to earth in the rain, snow, fog, or mist. A geographic area in which levels of a criteria air pollutant meet the health-based primary standard for the pollutant. An area may have an acceptable level for one criteria air pollutant, but may have unacceptable levels for others. Chlorofluorocarbons (CFCs) 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. Hazardous air pollutants are released by sources such as chemical plants, dry cleaners, printing plants, and motor vehicles.
