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Facility fence-line monitoring using passive samplers
Citation:
THOMA, E. D., M. C. MILLER, K. C. CHUNG, N. L. PARSONS, AND B. C. SHINE. Facility fence-line monitoring using passive samplers. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION. Air & Waste Management Association, Pittsburgh, PA, 61(8):834-842, (2011).
Impact/Purpose:
journal article
Description:
In 2009, the U.S. EPA executed a year-long field study at a refinery in Corpus Christi, Texas, to evaluate the use of passive diffusive sampling technology for assessing time-averaged benzene concentrations at the facility fence line. The study utilized 14-day time-integrated Carbopack X samplers deployed at 18 locations on the fence line and at two nearby air monitoring sites equipped with automated gas chromatographs. The average fence line concentration during the study was 1075 pptv with a standard deviation of 1935 pptv. For a six-month period during which wind direction was uniform, the mean benzene concentration value for a group of downwind sites exceeded the mean value of a similar upwind group by 1710 pptv. Mean value differences for these groups were not statistically significant for the remaining six-month time period when wind directions were mixed. The passive sampling approach exhibited acceptable performance with a data completeness value of 97.1% (n = 579). Benzene concentration comparisons with auto gas chromatographs yielded an r squared value of 0.86 and slope of 0.90 with an approximately 150 pptv observed bias (n = 50). The linear regression duplicate pairs yielded an r squared of 0.97, unity slope, and zero intercept (n = 56). In addition to descriptions of technique performance and general results, time series analyses are described, providing insight into the utility of two-week sampling for source apportionment under differing meteorological conditions. The limitations of the approach and recommendations for future measurement method development work are also discussed.
