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 Surry County, North Carolina, and

Swain County, North Carolina, give the percentage contributions from specific air pollution sources.  The Surry County Seat is Dobson, North Carolina, and the Swain County Seat is Bryson City, North Carolina.