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 Marquette County, Wisconsin, and

Menominee County, Wisconsin, give the percentage contributions from specific air pollution sources.  The Marquette County Seat is Montello, Wisconsin, and the Menominee County Seat is Keshena, Wisconsin.