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 Kalamazoo County, Michigan, and

Kalkaska County, Michigan, give the percentage contributions from specific air pollution sources.  The Kalamazoo County Seat is Kalamazoo, Michigan, and the Kalkaska County Seat is Kalkaska, Michigan.