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 Phelps County, Missouri, and

Pike County, Missouri, give the percentage contributions from specific air pollution sources.  The Phelps County Seat is Rolla, Missouri, and the Pike County Seat is Bowling Green, Missouri.