PM-10 EXHAUST SAMPLES COLLECTED DURING IM-240 DYNAMOMETER TESTS OF IN-SERVICE VEHICLES IN NEVADA

Twenty-three vehicles that were recruited by remote sensing and roadsi de inspection and maintenance (I/M) checks during the 1994 Clark and W ashoe Remote Sensing Study (CAWRSS) were tested on the IM240 cycle usi ng a transportable dynamometer. Six of these vehicles emitted visible smoke. Total gas-phase hydrocarbon (HC), carbon monoxide (CO), and nit rogen oxides (NOx) exhaust concentrations were continuously measured i n the diluted exhaust stream from the constant Volume sampler (CVS) du ring IM240 testing. Two isokinetic PM-10 samples were collected simult aneously using cyclones and filter holders connected to a dilution tub e. Teflon filters were collected for total mass and then extracted for chloride, nitrate, and sulfate ions. Quartz filters were analyzed by the thermal/optical reflectance method for organic and elemental carbo n. The quartz filters and backup vapor traps were then extracted and a nalyzed by GC/MS far 28 separate polynuclear aromatic hydrocarbons. Ma ss emission rates of PM-10 per vehicle ranged from 5.6 to over 1300 mg /ml, with most of the mass attributable to carbon. Except far one vehi cle with high sulfate emissions, the ion emissions were relatively low . Total PAH emissions were in the range of 10-200 mg/ml.