Spatial variability of unpaved road dust PM10 emission factors near El Paso, Texas.
The testing re-entrained aerosol kinetic emissions from roads technique is compared with distance-based emission factors (EFs; g/VKT) measured downwind of a dirt road by using towers instrumented with real-time meteorological and particle sensors at multiple heights. The emission potential (EP), defined as the EF divided by the vehicle speed (m/sec), and weight index permits the intercomparison of emissions from multiple roadways surveyed by the TRAKER vehicle. A survey of 72 km of unpaved roads on the Ft. Bliss Military Base near El Paso, Texas, indicated that 60% of all measured EPs fell between 6.7 (g/VKT)/(m/sec) and 9.6 (g/VKT)/(m/sec). The EP measured across the base was approximately 50% lower than those collected in the vicinity of the instrumented towers. This implies that EFs measured for other vehicles on the same test section should be reduced by 50% to more accurately represent EFs for the entire military base. Using geographic information system-based soil maps, the inferred EFs are related to differences in soil types over the survey area. Variations among five different soil types accounted for <10% of variation in EP. Individual measurements using the testing re-entrained aerosol kinetic emissions from roads technique did show larger spatial variations in EP; however, these were not effectively captured by the soil classifications, partly because of the comparatively coarse spatial classification used in the soil survey data.
Kuhns
Hampden
H
Desert Research Institute, Reno, NV 89512, USA. hkuhns@dri.edu
Gillies
John
J
Etyemezian
Vicken
V
Dubois
David
D
Ahonen
Sean
S
Nikolic
Djordje
D
Durham
Clyde
C
D000336:Aerosols / Q000032:analysis*; D003625:Data Collection; D004784:Environmental Monitoring; D040362:Geographic Information Systems; D007700:Kinetics; D012680:Sensitivity and Specificity; D012989:Soil Pollutants / Q000032:analysis*; D013781:Texas; D001335:Vehicle Emissions / Q000032:analysis*
D000336:Aerosols; D012989:Soil Pollutants; D001335:Vehicle Emissions