Evaluation of Dust Control Suppressants on Unpaved Roads Using Mobile Sampling

PM10 emission rates were measured on treated and untreated unpaved roads using fast-response optical PM10 sensors mounted in the front and behind the vehicle in the well-mixed wake. A special inlet probe was used to allow isokinetic sampling under all speed conditions. The emission factors were calculated by multiplying the concentration difference between front and back of the test vehicle by the frontal area. The test system has been designated as SCAMPER (System of Continuous Aerosol Monitoring of Particulate Emissions from Roadways). Measurements of PM10 emission rates were made on two different unpaved state highways in Arizona. Each route consisted of unpaved road with sections of several miles length treated with either Envirotac II Acrylic copolymer or CRS II Emulsified liquid. The SCAMPER tow vehicle was a 1995 Chevrolet Suburban and the average speeds ranged from 20 to 30 mph. The average emission rate of the treated section was approximately five times lower than the untreated gravel for the Envirotech II and sixty times lower for the CRS II treatment. Based on the replicate circuits, the precision of the measurement was approximately 20%. The SCAMPER was also used to determine PM10 emissions from a treated unpaved mine hau