Abstract: The Environmental Protection Agency (EPA) compiles data on emission tonnages of air pollutants for US counties.  US Air Quality Gradebook ("AirGrades") source sheets give the percentage contributions from specific air pollution sources.  This source sheet is for

Powder River County, Montana; Powell County, Montana; and Prairie County, Montana.  The Powder River County Seat is Broadus, Montana; the Powell County Seat is Deer Lodge, Montana; and the Prairie County Seat is Terry, Montana.