Overview On November 15, 1990, Congress enacted the Clean Air Act Amendments. The amendments made sweeping changes to the way air quality is regulated in the United States. The legislation was designed to curb three major threats to human health and the environment: acid rain, urban air pollution, and toxic air emissions.
Reference: Pennsylvania Department of Environmental Protection
State Implementation Plans State Implementation Plans U.S. Environmental Protection Agency (EPA), Region 5, Air and Radiation Division This system displays all federally approved SIP documents (includes drafts) for Illinois, Indiana, Michigan, Minnesota, Ohio and Wisconsin.
State Implementation Plans U.S. Environmental Protection Agency (EPA), Region 3 This is a summary of compilations for each of Region 3 states' SIP regulations, including Pennsylvania.