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 Poweshiek County, Iowa, and

Ringgold County, Iowa, give the percentage contributions from specific air pollution sources.  The Poweshiek County Seat is Montezuma, Iowa, and the Ringgold County Seat is Mount Ayr, Iowa.