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METHODS INTERCOMPARISON OF SAMPLERS FOR EPA'S NATIONAL PM 2.5 CHEMICAL SPECIATION NETWORK
Citation:
Solomon, P A., W J. Mitchell, D B. Gemmill, M P. Tolocka, G A. Norris, R W. Wiener, J. P. Homolya, S. I. Eberly, J. Rice, R. W. Vanderpool, R. W. Murdoch, S. Natarajan, AND E. D. Hardison. METHODS INTERCOMPARISON OF SAMPLERS FOR EPA'S NATIONAL PM 2.5 CHEMICAL SPECIATION NETWORK. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Description:
The objective of this sampler intercomparison field study is to determine the performance characteristics for the collection of the chemical components of PM2.5 by the chemical speciation monitors developed for the national PM2.5 network relative to each other, to the Federal Reference Method (FRM), and to other historically accepted monitors. The samplers were compared for PM2.5 mass, sulfate, nitrate, ammonium, OC, EC, and 10 elements. While the FRM is the standard for mass, there are no such standards for the chemical components of PM2.5 Thus, this intercomparison established equivalency among methods on a species by species basis. For volatile species (e.g., ammonium nitrate and semi-volatile organic compounds), the FRM provides only a lower limit on the expected mass loading for that species, as there is potential for loss of these species from the inert Teflon filters. For stable species, the FRM should provide an accurate estimate of the mass loading for those species. The historical samplers will provide an additional set of samples for comparison; however, they still can only be compared on an equivalent basis as none represent a reference method sampler.
To obtain a wide range of atmospheric chemical and meteorological conditions under limited time constraints, the study was conducted simultaneously in four locations over a two month period at Philadelphia, PA, Phoenix, AZ, Rubidoux, CA, and Research Triangle Park, NC. Statistical analysis of the data involved comparisons among the different samplers to examine differences in the determined chemical components due to sampler design characteristics. The results of this four-city sampler intercomparison study will be presented and differences found among the samplers ,performance will be discussed in light of sampler characteristics.
This work has been funded wholly or in part by the United States Environmental Protection Agency. Portions of the work were performed under Contract No. 68-D5-0040 by Research Triangle Institute. 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.