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

Merced County, California; Modoc County, California; and Mono County, California.  The Merced County Seat is Merced, California; the Modoc County Seat is Alturas, California; and the Mono County Seat is Bridgeport, California.