RECEPTOR MODELING APPROACH TO VOC EMISSION INVENTORY VALIDATION

The chemical-mass-balance (CMB) receptor model is a method for determi ning specific-source contributions of volatile organic compounds (VOCs ) to concentrations of nonmethane organic compounds (NMOCs) measured i n the ambient air. Because the method is based on air measurements, it offers an independent check on emission inventories developed by more traditional permit, survey, emission factor, and source-test techniqu es. This paper reports on the application of the CMB model to speciate d NMOC air-measurement data sets collected during the summers of 1984- 88 in five U.S. cities: Detroit; Chicago; Beaumont, Tex.; Atlanta; and Washington, D.C. Sources modeled were vehicle tailpipe emissions, fug itive gasoline-vapor emissions, architectural coating solvents, emissi ons from graphic arts, petroleum refineries, coke ovens, and polyethyl ene production. Comparisons of the CMB allocation of NMOC to emission inventory allocation of VOC for each city is discussed. Agreement with Environmental Protection Agency inventories for the five cities was g enerally very good for vehicles. Refinery inventory estimates are lowe r than CMB estimates-by more than a factor of 10 in Chicago and Detroi t. Trajectory analysis was used to validate coefficients for coke oven s.