Determination of PM10 emission rates from street sweepers

The use of street sweepers to clean paved roads, particularly after high-wi nd events, has been proposed as a PM10 control method. Using an artificial tunnel, the emission rates for several street sweepers were quantified unde r actual operating conditions. The tunnel was a tent enclosure, 6.1 x 4.3 x 73 m, open on both ends. PM10 concentrations were measured at the inlet an d outlet while a sweeper removed sand deposited along the length. Measureme nts were made using a specialized low-volume filter sampler and an integrat ing nephelometer. The volume of air passing through the tunnel was measured by releasing an inert tracer, sulfur hexafluoride, at the inlet and measur ing its concentration at the outlet. A large difference in emission rates b etween vacuum-type sweepers was observed, with rates varying from 5 to 100 mg m(-1) swept. For the cleanest sweepers, the background rates (collected by sweeping clean pavement) were about half of the total PM10 emission rate . These background emission rates likely were from diesel exhaust; backgrou nd rates for the single gasoline-powered sweeper were below detection. Part icle light scattering data confirmed the filter collection results. The art ificial tunnel approach would be useful in measuring total emissions from o ther mobile and stationary sources.