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 Louisa County, Iowa, and

Lucas County, Iowa, give the percentage contributions from specific air pollution sources.  The Louisa County Seat is Wapello, Iowa, and the Lucas County Seat is Chariton, Iowa.