ANALYSIS OF FINE PARTICULATE MATTER NEAR URBAN ROADWAYS

The emission and dispersion of particulate matter near urban roadways has become an issue of increasing concern because of the possible health risks to humans associated with the inhalation of small particulates. Despite the potential health risk, little is known about the concentration of particulates near urban roadways or the particulates emission rates of various vehicles. Particulate matter smaller than 2.5 micrometers (microns), typically denoted PM sub 2.5, was studied. Data were collected along paved roads on the University of Washington campus. The results of the data collection and subsequent statistical analysis indicated, as expected, that urban buses are by far the major source of particulate emissions and that buses with low exhaust pipes generate higher concentrations of roadside fine particulate matter than buses with elevated exhausts. The findings suggest that the Environmental Protection Agency's procedure AP-42 for calculating resuspended particulate matter near urban roads is grossly inaccurate, producing values that are 9 to 20 times higher than observed fine particulate levels.