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 Keokuk County, Iowa, and

Kossuth County, Iowa, give the percentage contributions from specific air pollution sources.  The Keokuk County Seat is Sigourney, Iowa, and the Kossuth County Seat is Algona, Iowa.