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 Wichita County, Texas, and

Wilbarger County, Texas, give the percentage contributions from specific air pollution sources.  The Wichita County Seat is Wichita Falls, Texas, and the Wilbarger County Seat is Vernon, Texas.