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 Presque Isle County, Michigan, and

Roscommon County, Michigan, give the percentage contributions from specific air pollution sources.  The Presque Isle County Seat is Rogers City, Michigan, and the Roscommon County Seat is Roscommon, Michigan.