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 Lake And Peninsula Borough, Alaska, and

Matanuska-Susitna Borough, Alaska, give the percentage contributions from specific air pollution sources.  The Lake And Peninsula Borough Seat is King Salmon, Alaska, and the Matanuska-Susitna Borough Seat is Palmer, Alaska.