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 Washoe County, Nevada, and

White Pine County, Nevada, give the percentage contributions from specific air pollution sources.  The Washoe County Seat is Reno, Nevada, and the White Pine County Seat is Ely, Nevada.