ABSTRACT
According to the latest report of the Environmental Protection Agency (EPA) documenting air quality trends in the United States (EPA, 1999b), mobile sources accounted for 51% of carbon monoxide (CO) emissions, 34% of nitrogen oxide (NO
) emissions, and 29% of volatile organic compound (VOC) emissions; NO
and VOCs react in sunlight to form ozone. In the California South Coast Air Basin, running stabilized emissions account for between 60% (organic gases) and 90% (nitrogen oxides) of estimated total mobile source emissions inventories.
