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RECEPTOR MODEL COMPARISONS AND WIND DIRECTION ANALYSES OF VOLATILE ORGANIC COMPOUNDS AND SUBMICROMETER PARTICLES IN AN ARID, BINATIONAL, URBAN AIRSHED
Citation:
Mukerjee, S, G A. Norris, L. Smith, C. A. Noble, L M. Neas, A H. Ozkaynak, AND M Gonzales. RECEPTOR MODEL COMPARISONS AND WIND DIRECTION ANALYSES OF VOLATILE ORGANIC COMPOUNDS AND SUBMICROMETER PARTICLES IN AN ARID, BINATIONAL, URBAN AIRSHED. ENVIRONMENTAL SCIENCE AND TECHNOLOGY 38(8):2317-2327, (2004).
Impact/Purpose:
Overall Goal: To develop spatial analyses using limited network-based air quality and GIS and other ancillary spatial information to estimate exposures for epidemiologic studies.
Goal of NERL Contribution: To develop regression-based spatial models using said measures and ancillary information to predict such exposures at unmonitored locations.
Specific Objectives:
1. To determine whether ultrafine (<0.1 um), accumulation (0.1-0.7), and/or coarse (1-10 um) mode particle counts correlate with CO, NO2 and VOCs emitted from mobile and/or other urban sources using source apportionment modeling techniques.
2. To determine spatial associations among measured levels of NO2, VOCs, and (possibly) ultrafine/accumulation/coarse mode particle counts from mobile and other urban sources in El Paso. Spatial variability in ultrafine/accumulation/coarse mode particle concentrations will be determined using available PM, NO2, VOC and available surrogates of motor vehicle emissions. These measured or predicted spatial associations will then be used by NHEERL to ultimately assess impact of these particle counts and gaseous species on children's exposures in schools.
3. To evaluate accuracy of NO2 and VOC measurements using the passive badges to be deployed by EPA versus collocated FRM devices established by the State of Texas. In addition, to evaluate precision of collocated NO2 and VOC passive badge measurements.
4. To use spatial analysis concepts to evaluate their possible application in an EPA Region 6 study entitled "Air Toxics Data and Analysis and Development of a Predictive Model of Estimation of Ambient Vocs in Selected Census Tracts in Houston-Galveston, TX."
Description:
The relationship between continuous measurements of volatile organic compounds sources and particle number was evaluated at a Photochemical Assessment Monitoring Station Network (PAMS) site located near the U.S.-Mexico Border in central El Paso, TX. Sources of volatile organic compounds (VOCs) were investigated using the multivariate receptor model UNMIX and the effective variance least squares receptor model known as Chemical Mass Balance (CMB, Version 8.0). As expected from PAMS measurements, overall findings from data screening as well as both receptor models confirmed that mobile sources were the major source of VOCs. Comparison of hourly source contribution estimates (SCEs) from the two receptor models revealed significant differences in motor vehicle exhaust and evaporative gasoline contributions. However, the motor vehicle exhaust contributions were highly correlated with each other. Motor vehicle exhaust was also correlated with the ultrafine and accumulation mode particle count, which suggests that motor vehicle exhaust is a source of these particles at the measurement site. Wind sector analyses were performed using the SCE and pollutant data to assess source location of VOCs, particle count, and criteria pollutants. Results from this study have application to source apportionment studies and mobile source emission control strategies that are ongoing in this air shed.
The US Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract 68-D-99-012 to Research Triangle Institute and contract 68-D0-0206 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.