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 Pueblo County, Colorado, and

Rio Blanco County, Colorado, give the percentage contributions from specific air pollution sources.  The Pueblo County Seat is Pueblo, Colorado, and the Rio Blanco County Seat is Meeker, Colorado.