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The gaseous and particulate emissions from a light-duty diesel powered passenger car were measured by a variety of chemical analysis techniques for three different fuels, typical No. 1 and No. 2 commercial diesel fuels and the Federal Register No. 2-D smoke test fuel. Hydrocarbon emissions were found to be inversely related to fuel molecular weight. The NO2/NO ratio was found to be much higher than for gasoline engines approaching 0.3 at low load. Particulate emissions were approximately 0.3 grams/mile for all fuels and driving cycles tested. Sulfate emissions were high, approaching that of some catalyst cars. Sulfate emissions decreased with decreasing fuel sulfur and increased by a factor of two in highway driving over urban driving. The potential pollution problems with such cars are worthy of further study.

Exhaust emissions from two diesel passenger cars were measured as a function of ambient temperature (43 - 82°F) over the urban dynamometer driving schedule of the Federal Test Procedure (FTP). Low ambient temperature did not affect rates of emission of total hydrocarbons, carbon monoxide, or nitrogen oxides. Fuel economy decreased with decreasing test temperature. Total particulate matter increased with decreasing test temperature, as did particulate organic emission rates (due primarily to adsorption of uncombusted diesel fuel). Polynuclear aromatic hydrocarbon emissions (ug/mile) and mutagenicity in the Ames Salmonella bioassay (rev/mile) were not affected by decreasing test temperature.