Wikimedia
Wikipedia: Clean Air Act (United States)
Wikipedia offers extensive information on the history and amendments to the Clean Air Act of the United States.
US Environmental Protection Agency
Epa: Benefits and Costs of the Clean Air Act, 1970 to 1990
This resource compares the environmental benefits of pollution control to the costs incurred by industry, taxpayers, and consumers.
Other
South Carolina Forestry Commission: Clean Air Act of 1970
This site talks about the development of the Clean Air Act and its effects in South Carolina.
Siteseen
Siteseen: American Historama: Clean Air Act of 1963, 1970 and 1990
Discussion of the three sets of federal programs to establish air quality goals and to impose pollution control.