PARTICLE RESUSPENSION FROM ASPHALT ROADS CAUSED BY CAR AND TRUCK TRAFFIC

摘要

Particle resuspension caused by moving-vehicular-generated surface stresses was determined by using solid ZnS tracer particles placed on a road. The ZnS particles (less than 25 um in diameter) were initially placed on a test area 10 ft wide by 100 ft long on one lane of a two lane, seasoned, asphalt road. To measure particle resuspension at a constant vehicle speed, either a car or a 3/4-ton truck was driven in the lane through the tracer area or in the lane adjacent to the tracer area. The fraction of particles resuspended from the road by the surface stresses was determined using a tracer mass balance. For the mass bal ance, the downwind airborne tracer exposure and tracer ground deposition were measured. The fraction of tracer particles resuspended was normalized for each vehicle speed by the number of times (passes) the vehicle was driven the length of the test area. The fraction of particles re¬suspended per vehicle pass was determined for separate vehicle speeds of 5, 15, 30, and 50 mph.