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LOWER RIO GRANDE VALLEY TRANSBOUNDARY AIR POLLUTION PROJECT (TAPP) (MAIN REPORT)
Citation:
Mukerjee, S, D. S. Shadwick, K. E. Dean, L. Y. Carmichael, J. J. Bowser, AND L J. Purdue. LOWER RIO GRANDE VALLEY TRANSBOUNDARY AIR POLLUTION PROJECT (TAPP) (MAIN REPORT). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-99/047 (NTIS PB99-146938), 1999.
Description:
The purpose of the Lower Rio Grande Valley Transboundary Air Pollution Project (TAPP) was to obtain air quality data for a full year at three border monitoring sites to assess anthropogenic and biogenic emission impacts and transboundary air pollution transport in the Lower Rio Grande Valley of Texas. Performed by the U.S. Environmental Protection Agency (U.S. EPA), in cooperation with the Texas Natural Resource Conservation Commission (TNRCC) as part of the U.S.-Mexico Border XXI Program, the TAPP collected air quality, precipitation, and meteorological data at three sites in and near Brownsville, Texas and close to the U.S.Mexican border. Monitoring was performed on a near real-time basis for fine paniculate matter (PM; 5); time-integrated continuous monitoring was performed for PM; 5 with associated elements, coarse paniculate matter (PM^.io) with associated elements, paniculate carbon, volatile organic compounds, polycyclic aromatic hydrocarbons, and pesticides.
Using these data, comparisons with Effects Screening Level (ESL) data were initially done. ESLs are health/welfare-based screening levels established by the TNRCC and are not ambient air standards. Comparisons with data from U.S. EPA and other environmental exposure monitoring studies were also done. Chemical tracer analyses, wind sector analyses, and rudimentary source apponionment analyses were also conducted.
The vast majority of the approximately 2650 air pollutant samples acquired in this study were low or comparable to ESLs .or environmental monitoring data from the literature. Overall, air quality in the Brownsville area of the Valley was good. The few observations of pollutants exceeding these levels appeared to be caused by uncenainties due to intrinsic variability of the data or occasional local events (such as automotive traffic, local scrap fires, etc.), not by regional phenomena or persistent transboundary plumes. With the exception of silver, methanol, and acrolein, the rest of the seven air pollutants were above their ESLs only once. Of these three persistent pollutants, sampling difficulties associated with acrolein and methanol means that these values should be interpreted with caution.
Transboundary transpon of air pollution plumes did not appear to cause noticeable deterioration of air quality on the U.S. side of the Lower Rio Grande Valley border. The dominance of winds from the Gulf of Mexico was largely responsible for the clean air conditions in the Brownsville air shed.
The information in this document has been funded wholly or in part by the United States Environmental Protection Agency under Contract 68-D2-0134 to QST Environmental, Inc., and contract 68-D5-0049 to ManTech Environmental, Inc. It has been subjected to agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.