Legend (Nitrogen_Oxide)

Solvent (0) Mobile (1) Burning (2) Waste_Disposal (3) Misc_Non_Ind_NEC (4) Industrial_Processes (5) Gas_Stations (6) Fuel_Comm_Institutional (7) Fuel_Comm_Electrical_Generation (8) Fuel_Comb_Residential (9) Fuel_Comb_Ind_Boilers (10) Bulk_Gas_Terminals (11) Biogenics_Veg_Soil (12)