Abstract
Excess air pollution along roadways is an issue of public health concern to Federal, State, and local government environmental agencies and the public. This concern was the motivation for a long-term study to measure levels of air pollutants at various distances from a roadway in Las Vegas, Nevada. This study represents a joint effort between the US Environmental Protection Agency and the US Department of Transportation’s Federal Highway Administration. Measurements of air pollutants—including carbon monoxide (CO), oxides of nitrogen (NO, NO2, NOX), and black carbon (BC)—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, concentrations of all measured species at 20 m from the highway were significantly higher (non-overlapping 95% confidence intervals) than levels 300 m from the road. In addition, CO, NOX, and BC measured at 100 m from the road on the prevailing downwind side of the road were significantly higher than 100 m on the opposite side of the road. 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°), CO, NO2, NOX, and BC levels at 20 m east of the highway were 60%, 46%, 122%, 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 20 m east of the road; average wind speed appears to be an important explanatory factor. The year-long extensive dataset afforded some unique data mining analyses—the maximum near-road impact (top 10% of 20 m east site minus 300 m east site) is associated with winds from the southwest to northwest, higher traffic volumes, and low wind speeds; meanwhile, the apparent maximum spatial extent in near-road impact (top 10% of 300 m east site minus to 100 m west site) occurred during evening to presunrise periods in the winter under conditions of low speed winds from due west, with moderate to low traffic volumes. This research confirms that excess air pollution associated with proximity to roads is significant over a year-long time frame and that local meteorology is a critical factor determining the extent of near-road impact.
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References
Baldauf R et al (2008) Traffic and meteorological impacts on near-road air quality: summary of methods and trends from the Raleigh near-road study. J Air Waste Manag Assoc 58:865–878
Brugge D, Durant JL, Rioux C (2007) Near-highway pollutants in motor vehicle exhaust: a review of epidemiologic evidence of cardiac and pulmonary health risks. Environ Health 6:1–12
Chen J et al (2009) Characteristics of gaseous pollutants near a main traffic line in Beijing and its influencing factors. Atmos Res 94:470–480
Dutkiewicz VA, Alvi S, Ghauri BM, Choudhary MI, Husain L (2009) Black carbon aerosols in urban air in South Asia. Atmos Environ 43:1737–1744
Ecotech (2007a) WinAQMS air quality monitoring software: user manual (version 2.3.5 ed) Victoria, Australia
Ecotech (2007b) WinCollect data evaluation and reporting software (version 3.3 ed) Victoria, Australia
Hagler GSW, Yelverton TLB, Vedantham R, Hansen ADA, Turner JR (2011) Post-processing method to reduce noise while preserving high time resolution in aethalometer real-time black carbon data. Aerosol Air Qual Res 11:539–546
HEI (2010) Traffic-related air pollution: a critical review of the literature on emissions, exposure, and health effects. Special Report 17 Boston, MA
Hu S et al (2009) A wide area of air pollutant impact downwind of a freeway during pre-sunrise hours. Atmos Environ 43:2541–2549
Karner AA, Eisinger DS, Niemeier DA (2010) Near-roadway air quality: synthesizing the findings from real-world data. Environ Sci Technol 44:5334–5344
Kimbrough S et al (2008) Multi-criteria decision analysis for the selection of a near road ambient air monitoring site for the measurement of mobile source air toxics. Transp Res D Transp Environ 13:505–515
Kozawa KH, Fruin SA, Winer AM (2009) Near-road air pollution impacts of goods movement in communities adjacent to the Ports of Los Angeles and Long Beach. Atmos Environ 43:2960–2970
Mejía JF, Choy SL, Mengersen K, Morawska L (2011) Methodology for assessing exposure and impacts of air pollutants in school children: data collection, analysis and health effects—a literature review. Atmos Environ 45:813–823
Nevada DOT (2006) 2006 Annual Traffic Report. Carson City, Nevada
NIST (2010) NIST Internet Time Service (ITS). http://www.nist.gov/pml/div688/grp40/its.cfm. Accessed October 2010
US EPA (2010) Primary National Ambient Air Quality Standards for Nitrogen Dioxide. US GPO, Washington, DC
US FHWA (2006) Detailed monitoring protocol for U.S. 95 settlement agreement. FHWA, Washington, DC
Virkkula A et al (2007) A simple procedure for correcting loading effects of aethalometer data. J Air Waste Manage Assoc 57:1214–1222
Virtanen A et al (2006) Winter and summer time size distributions and densities of traffic-related aerosol particles at a busy highway in Helsinki. ACP 6:2411–2421
Zhou Y, Levy J (2007) Factors influencing the spatial extent of mobile source air pollution impacts: a meta-analysis. BMC Public Health 7:89
Zhu Y, Hinds W, Shen S, Sioutas C (2004) Seasonal trends of concentration and size distribution of ultrafine particles near major highways in Los Angeles. Aerosol Sci Technol 38:5–13
Zhu Y, Kuhn T, Mayo P, Hinds WC (2006) Comparison of daytime and nighttime concentration profiles and size distributions of ultrafine particles near a major highway. Environ Sci Technol 40:2531–2536
Acknowledgments
We thank members of the EPA Near-Road team for their contributions over the life of this project. We thank Brian Schumacher and Jeffery Lantz of the EPA Las Vegas Facility for their support of the Las Vegas project. We thank American Ecotech for shelter/instrument operation support. We thank Jeffrey Baker of TSI for the loan of the TSI Model 3031 Ultrafine Particle instrument. We thank David Proffitt, Michal Derlicki, Richard Snow, Nikki Williams of ARCADIS for site operation and logistical support and Hunter Daughtrey, Dennis Williams, Karen Oliver, Lydia Brouwer, and Herb Jacumin of Alion Science and Technology for preparation and analysis of sampling media.
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This document has been reviewed in accordance with US Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. The views expressed in this journal article are those of the authors and do not necessarily reflect the views or policies of the US Environmental Protection Agency.
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Kimbrough, S., Baldauf, R.W., Hagler, G.S.W. et al. Long-term continuous measurement of near-road air pollution in Las Vegas: seasonal variability in traffic emissions impact on local air quality. Air Qual Atmos Health 6, 295–305 (2013). https://doi.org/10.1007/s11869-012-0171-x
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DOI: https://doi.org/10.1007/s11869-012-0171-x