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 Androscoggin County, Maine, and

Aroostook County, Maine, give the percentage contributions from specific air pollution sources.  The Androscoggin County Seat is Auburn, Maine, and the Aroostook County Seat is Houlton, Maine.