A Method for Evaluating the Atmospheric Ozone Impact of Actual Vehicle Emissions

A method for analyzing and evaluating the potential atmospheric ozone formed by the actual emissions of carbon monoxide and volatile organic compounds from motor vehicles is described. The method is illustrated using the results of some recently published emission tests performed on a variety of vehicles equipped to utilize gasoline and several alternative fuels including methanol, ethanol, alcohol/gasoline blends, LPG and CNG. The reactivity contributions of the various constituent species as well as the overall ozone potential of the emissions are determined. Some of the scientific and application issues raised by the method are also discussed including the effects of nitrogen oxide concentrations, varying airshed characteristics, emission standards and test procedures.