TRENDS AND UNCERTAINTIES IN ANTHROPOGENIC VOC AND NOX EMISSIONS

Since 1900, NO(x) emissions appear to have steadily increased in nearly all areas of the country while emissions of nonmethane volatile organic compounds have fluctuated, but overall have remained fairly constant. Since 1985, the trend in emissions of both pollutants has shown little change. This paper presents the long-term historic and recent emission trends of these pollutants on the national level and in the northeast United States. Conventional methods of estimating anthropogenic emissions are discussed and various attempts at estimating uncertainty are described. The best estimate of the uncertainty of historic emission trends are presented. The uncertainty of emission estimates may be reduced in the future by improving estimation methods.