Light-duty motor vehicle exhaust particulate matter measurement in the Denver, Colorado, area

A study of particulate matter (PM) emissions from in-use, light-duty vehicl es was conducted during the summer of 1996 and the winter of 1997 in the De nver, CO, region. Vehicles were tested as received on chassis dynamometers on the Federal Test Procedure Urban Dynamometer Driving Schedule (UDDS) and the IM240 driving schedule. Both PM10 and regulated emissions were measure d for each phase of the UDDS. For the summer portion of the study, 92 gasol ine vehicles, 10 diesel vehicles, and 9 gasoline vehicles with visible smok e emissions were tested once. For the winter, 56 gasoline vehicles, 12 dies el vehicles, and 15 gasoline vehicles with visible smoke were tested twice, once indoors at 60 degrees F and once outdoors at the prevailing temperatu re. Vehicle model year ranged from 1966 to 1996. Impactor particle size dis tributions were obtained on a subset of vehicles. Continuous estimates of t he particle number emissions were obtained with an electrical aerosol analy zer This data set is being provided to the Northern Front Range Air Quality Study program and to the State of Colorado and the U.S. Environmental Prot ection Agency for use in updating emissions inventories.