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Long-term continuous measurement of near-road air pollution in Las Vegas: Seasonal variability in traffic emissions impact on local air quality
Citation:
KIMBROUGH, E. S., R. W. BALDAUF, G. S. HAGLER, R. C. SHORES, W. A. MITCHELL, D. A. WHITAKER, C. W. CROGHAN, AND D. A. VALLERO. Long-term continuous measurement of near-road air pollution in Las Vegas: Seasonal variability in traffic emissions impact on local air quality. Air Quality, Atmosphere & Health. Springer-Verlag, New York, NY, 6(1):295-305, (2013).
Impact/Purpose:
journal article
Description:
Excess air pollution along roadways is an issue of public health concern and motivated a long-term measurement effort established by the U.S. Environmental Protection Agency in Las Vegas, Nevada. Measurements of air pollutants – including black carbon (BC), carbon monoxide (CO), and oxides of nitrogen (NO, NO2, NOX) – were conducted concurrently at four distances from a major interstate (206,000 vehicles per day) for an entire year. With prevailing winds from the west, locations 10 m and 100 m east of the highway had statistically significant excess CO compared to sites located farther to the east (300 m) or opposite the direction of prevailing wind (100 m to the west). The disproportionate impact of the roadway emissions on the eastern side of the highway points to the importance of local meteorology in determining the extent of near-road impact. When isolating only time periods with winds from due west (±60 degrees), all stations to the east had statistically significant excess CO relative to the station located 100 m to the west, with NO2, NOX, CO, and BC levels at 10 m east of the highway 46%, 122%, 60%, and 127% higher, respectively, than the concurrent measurements at the upwind site. Monthly average traffic volume and frequency of downwind conditions are not enough to explain the trends in monthly average excess CO at 10 m east of the road; average wind speed appears to be an important explanatory factor. This research confirms that excess air pollution associated with proximity to roads is statistically significant over a year-long time frame and that local meteorology is a critical factor determining the extent of near-road impact.
