H. Moosmuller et al., PARTICULATE EMISSION RATES FOR UNPAVED SHOULDERS ALONG A PAVED ROAD, Journal of the Air & Waste Management Association, 48(5), 1998, pp. 398-407
This paper reports the first empirical estimate of particle emissions
from unpaved shoulders along paved roads.(1) Its objectives are to dev
elop and demonstrate an emission rate measurement methodology that can
be applied in different areas; identify the mechanisms that suspend d
ust from unpaved shoulders and the observables related to this suspens
ion process; and quantify PM10 mass emissions in the form of an emissi
on rate. To achieve these objectives, fast-response observations from
nephelometers and a sonic anemometer were used to characterize short-l
ived dust plumes generated by passing vehicles. In addition, detailed
soil surface measurements determined the mechanical properties of the
shoulder surfaces. Large traffic-induced turbulence events that led to
significant dust entrainment were almost exclusively caused by ''larg
e'' vehicles such as trucks, semis, and vehicles pulling trailers, all
traveling 50-65 mph. PM10 emission rates for these large, fast-travel
ing vehicles were determined to be 8 +/- 4 grams per vehicle kilometer
traveled under dry conditions. Emissions due to smaller vehicles such
as cars, vans, and sport utility vehicles were negligible for normal
on-road driving. These results indicate that the majority of PM10 emis
sions from unpaved shoulders is caused by relatively few vehicles.