Abstract: The Environmental Protection Agency (EPA) compiles data on emission tonnages of air pollutants for US counties.  US Air Quality Gradebook ("AirGrades") source sheets such as this one for Macomb County, Michigan, and

Manistee County, Michigan, give the percentage contributions from specific air pollution sources.  The Macomb County Seat is Mount Clemens, Michigan, and the Manistee County Seat is Manistee, Michigan.