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SURVEY OF VOLATILE ORGANIC COMPOUNDS ASSOCIATED WITH AUTOMOTIVE EMISSIONS IN THE URBAN AIRSHED OF SAO PAULO, BRAZIL
Citation:
Colon, M, J D. Pleil, T A. Hartlage, M. L. Guardani, AND M. H. Martins. SURVEY OF VOLATILE ORGANIC COMPOUNDS ASSOCIATED WITH AUTOMOTIVE EMISSIONS IN THE URBAN AIRSHED OF SAO PAULO, BRAZIL. ATMOSPHERIC ENVIRONMENT 35(23):4017-4031, (2001).
Impact/Purpose:
The objective of this task is to develop state-of-the-art methods for measuring xenobiotic compounds, to include the isolation of the analyte from the appropriate matrix (extraction), preconcentration (typically sorbent-based), and analysis via GC/MS and/or LC/MS. Once established, these methods will be applied in small scale pilot studies or demonstration projects. Particular emphasis will be placed on methods which are readily transferable to other laboratories, including those within the Human Exposure and Atmospheric Sciences Division (HEASD), the National Exposure Research Laboratory (NERL), other EPA Laboratories, Program Offices, Regions, and academic institutions.
Specific objectives of this task include the following:
1) Development of GC/MS and LC/MS methods for the measurement of key xenobiotic compounds and their metabolites (to include the pyrethroid pesticides, perfluorinated organic compounds, and the BFRs) in relevant environmental and biological matrices.
2) Development of efficient low cost methods for the extraction and clean up of these compounds collected from relevant matrices.
3) Determination of xenobiotic compound and metabolite concentrations in samples derived from laboratory and field monitoring studies to help assess exposures and evaluate associated risks.
Description:
The Metropolitan Region of Sao Paulo (MRSP), Brazil, is one of the largest metropolitan areas in the world (population 17 million, approx.) and relies heavily on alcohol-based fuels for automobiles. It is estimated that about 40% of the total volume of fuel is ethanol with some vehicles using pure ethanol and others a gasoline/ethanol blend. As such, Sao Paulo is an excellent example of an oxygenates-dominated airshed of mobile sources and is most likely indicative of the future in heavily populated areas in the U.S. such as Los Angeles where "oxy fuels" are becoming an important replacement for the conventional pure petroleum-based fuels. In this work, we surveyed the ambient air to identify and quantify the organic compounds associated with the evaporative and exhaust emissions of these fuels and to begin to understand the potential for human exposure. Because this was an initial test without detailed prior knowledge of the air shed of the area, we applied two different air sampling methods for various time periods to assess the ambient concentrations of a variety of polar and nonpolar volatile organic compounds (VOCs). For quality assurance (QA), we collected all the samples in duplicate (whole-air samples in Summa canisters and adsorbent-based samples on Carbotrap/Carboxen 1000 tubes) at various flow rates to test performance. All samples were collected over identical time frames, typically for 1-, 2-, and 4-h periods per day at six different locations over a period of 1 week. Overall Sao Paulo results demonstrate that mean concentrations of single-ring aromatics are 2 to 3 times higher, volatile aldehydes are 5 to 10 times higher, and simple alcohols 10 to 100 times higher as compared to results of a recent study performed by EPA in the Los Angeles basin. C4 to C11 n-alkanes were only slightly elevated in Sao Paulo.
The scientific portion of this work was funded by EPA, including infrastructure support from ManTech Environmental Technology, Inc., under EPA Contract 68-D5-0049 for calibration and quality assurance standards. This work has been subjected to EPA review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.