From WebRef.org
Jump to: navigation, search

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).