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 Tangipahoa Parish, Louisiana, and

Tensas Parish, Louisiana, give the percentage contributions from specific air pollution sources.  The Tangipahoa Parish Seat is Amite, Louisiana, and the Tensas Parish Seat is Saint Joseph, Louisiana.