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

Cass County, Nebraska; Cedar County, Nebraska; and Chase County, Nebraska.  The Cass County Seat is Plattsmouth, Nebraska; the Cedar County Seat is Hartington, Nebraska; and the Chase County Seat is Imperial, Nebraska.