RECEPTOR MODELING APPROACH TO VOC EMISSION INVENTORY VALIDATION

The chemical-mass-balance (CMB) receptor model is a method for determining specific-source contributions of volatile organic compounds (VOCs) to concentrations of nonmethane organic compounds (NMOCs) measured in 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 techniques. This paper reports on the application of the CMB model to speciated 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, fugitive gasoline-vapor emissions, architectural coating solvents, emissions from graphic arts, petroleum refineries, coke ovens, and polyethylene 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 generally very good for vehicles. Refinery inventory estimates are lower than CMB estimates-by more than a factor of 10 in Chicago and Detroit. Trajectory analysis was used to validate coefficients for coke ovens.