Volume 12, No. 2, April 2012, Pages 169-179 PDF(1.56 MB)
Aerosol and Air Toxics Exposure in El Paso, Texas: A Pilot Study
L.-W. Antony Chen1, Richard J. Tropp1, Wen-Whai Li2, Dongzi Zhu1, Judith C. Chow1,3, John G. Watson1,3, Barbara Zielinska1
1 Division of Atmospheric Sciences, Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512, U.S.A.
2 Department of Civil Engineering, University of Texas at El Paso, El Paso, TX 79968, U.S.A.
3 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 10 Fenghui South Road, Xi’and High-Tech Zone, Xi’an 710075, China
The Paso del Norte (PdN) region is one of the largest metropolitan areas along the U.S.-Mexico border. Different emission regulations between the two countries, particularly with respect to on-road vehicle and domestic burning, have impacted the regional concentration and human exposure of air toxics (e.g., metals, polycyclic aromatic hydrocarbons [PAHs], and carbonyls). Comprehensive air quality measurements were conducted using a mobile monitoring system at two urban-scale sites within El Paso, Texas in December 2008 as a pilot study to understand aerosol and air toxics exposure and sources in the PdN region. The measurements show clear diurnal variations due to traffic emissions and a major pollution episode likely caused by both motor vehicles and domestic burning. Wind analysis further confirms the importance of cross-border transport on elevated pollutant concentrations at the monitoring sites. The traffic-dominated periods are characterized by high fractions of black carbon, particle-bound PAHs (p-PAHs), and carbonyls in comparison with dust-related periods. During the particular pollution episode, high levels of elemental chlorine and vinyl chloride were observed that might relate to unregulated domestic burning of polyvinyl chloride (PVC) products. Although most pollution indicators show a substantial improvement in air quality over the last decade, short-term exposure to some p-PAHs, e.g., benzo[a]pyrene, is still close to the health effects screening level. Bi-national efforts are required to further reduce air toxics emissions.
Cross-border air quality; PAHs; PM2.5; Carbonyls; Mobile monitoring system; Pollution wind rose.