The objectives of this research are to develop a methodology for assessing PM10 emissions from roads, and to compare emission factors developed from this method to those published factors currently in use by regulatory agencies.
Upwind and downwind concentrations of PM10 were monitored at several paved and unpaved roadway sites in eastern Washington and northern Idaho. A novel method for measuring PM10 emission rates that used an inert, atmospheric tracer to simulate the road sources of PM10 was developed. Using this methodology, PM10 emission rates were measured from paved and unpaved roads.
The results of this study demonstrate that the use of an inert tracer in a line source to simulate roadway PM10 emissions can provide a tool for improving the existing emission inventories for fugitive PM10 emissions from roads. The emission factors calculated for unpaved roads were similar in magnitude to those currently used by the Department of Ecology. The factors for paved roads were nearly an order of magnitude higher than those currently in use. PM10 emission rates for paved roads were found to be highly variable, depending on parameters that include wind speed, the variability in the wind direction, and traffic and roadway conditions.