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 Bristol County, Massachusetts, and

Dukes County, Massachusetts, give the percentage contributions from specific air pollution sources.  The Bristol County Seat is Taunton, Massachusetts, and the Dukes County Seat is Edgartown, Massachusetts.