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PARTICULATE ORGANIC CARBON MEASUREMENTS COLLECTED WITH LOW FLOW PERSONAL SAMPLERS
Citation:
Norris, G A., M P. Tolocka, R W. Williams, AND C. E. Rodes. PARTICULATE ORGANIC CARBON MEASUREMENTS COLLECTED WITH LOW FLOW PERSONAL SAMPLERS. Presented at 11th Annual Meeting of the International Society of Exposure Analysis, Charleston, SC, November 4-8, 2001.
Description:
EPA's National Exposure Research Laboratory and the Research Triangle Institute (RTI) have conducted a particulate matter (PM) personal exposure study in Research Triangle Park, NC. Particulate carbon was sampled with pre-fired quartz filters using low flow PM2.5 samplers (2 LPM, 37 mm filter) in multiple environments: personal, community (ambient), outdoor, and indoor. The quartz filter samples were analyzed for particulate organic carbon (OC) and elemental carbon (EC) using a modified NIOSH Method 5040 protocol by RTI. Pre-fired quartz filters were used to provide a low blank value. However, this laboratory and others have demonstrated that the quartz substrate is an active surface for the collection of semi-volatile organic compounds (SVOCs; McDow et al., 1990; Turpin et al., 1994; Volkens et al., 1999; Tolocka et al., 2001). In this study, SVOC artifact was evident in the personal and indoor samples from a comparison of the particulate carbon mass concentrations with collocated PM2.5 mass concentrations collected with a Teflon filter. The estimated organic mass (OM) was determined by multiplying the OC concentration by 1.4 to account for the hydrogen and oxygen mass not quantified in the carbon analysis. Average personal and indoor OM + EC were 116 % (standard deviation (sd) 62 %) and 135 % (sd 70 %) of the PM2.5 mass concentration, respectively. However, the outdoor OM + EC only explained 47 % of the PM2.5 mass concentration. Indoor or personal monitoring appears to be more highly effected by SVOC artifact due to the prevalence of SVOCs in the indoor environment and the use of samplers with low filter face velocities.
The information in this document has been funded wholly or in part by the United States Environmental Protection Agency under Contracts 68-D5-0040 and 68-D-99-012 to Research Triangle Institute, and cooperative agreement CR822981-01 to 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.