Emissions of Polynuclear Hydrocarbons from Automobiles and Trucks

As part of a screening survey to determine the origin of the benzo[a]pyrene found in urban atmospheres in the United States, emission rates of several polynuclear hydrocarbons, including benzo [a] pyrene, were measured on several automobiles and trucks powered by gasoline engines. The vehicles were road-tested over typical driving routes. The total exhaust was sampled by passing it through a multi-plate condenser followed by large high-efficiency filters. Operating and emission data are given. The combined effects of vehicle-model age and mileage on polynuclear emissions are discussed, as are the relationships between polynuclear hydrocarbon emissions and the emissions of other products of incomplete combustion.