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 Dade County, Florida, and

DeSoto County, Florida, give the percentage contributions from specific air pollution sources.  The Dade County Seat is Miami, Florida, and the DeSoto County Seat is Arcadia, Florida.