- Contamination of the atmosphere by substances that, directly or indirectly, adversely affect human health or welfare. Air pollution results from human activities, both deliberate releases (as from smokestacks) and fugitive emissions (as dust blown from streets or fields), and from natural sources, including sea spray, volcanic emissions, pollen, etc. The Clean Air Act authorizes the Environmental Protection Agency to regulate air pollution (see National Ambient Air Quality Standards).
- The contamination of the atmosphere by any toxic or radioactive gases and particulate matter as a result of human activity. [Environmental Science and Technology; v28; 1633-1649; Sept 1994.] [New Scientist; v143; 8; 1994.] Source: Atmospheric Chemistry Glossary