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ASSAYING PARTICLE-BOUND POLYCYCLIC AROMATIC HYDROCARBONS (PAH) FROM ARCHIVED PM2.5 FILTERS
Citation:
Pleil, J D., A F. Vette, AND S. M. Rappaport. ASSAYING PARTICLE-BOUND POLYCYCLIC AROMATIC HYDROCARBONS (PAH) FROM ARCHIVED PM2.5 FILTERS. JOURNAL OF CHROMATOGRAPHY A 1033(1):9-17, (2004).
Impact/Purpose:
The main objectives of this research are to measure ambient concentrations of PM and related air toxics in lower Manhattan as they pertain to transport of PM and air toxics emitted in the vicinity of the WTC recovery site.
Description:
Airborne particulate matter contains numerous organic species, including several polycyclic aromatic hydrocarbons (PAHs) that are known or suspected carcinogens. Existing methods for measuring airborne PAHs are complex and costly, primarily because they are designed to collect both gas-phase and particle-phase PAH constituents. Here, we report an assay for measuring particle-bound PAHs in archived filters from the network of U.S. monitoring stations for particles less than 2.5 um in diameter (PM2.5), without the need for deploying specialized samplers. PAHs are extracted from Teflon filters with dichloromethane, concentrated, and measured at trace levels using gas-chromatography mass-spectrometry. Although PAHs with 3 to 6 aromatic rings can be assayed, results are only unambiguously accurate for compounds with 5- or 6-rings, due to variable vaporization losses of the more volatile 3- & 4-ring compounds during sampling and/or storage. The method was evaluated for sensitivity, recovery, precision, and agreement of paired air samples, using PM2.5 samplers deployed locally in Chapel Hill, NC. Additionally, three sets of archived samples were analyzed from a study of PM2.5 in the Czech Republic. Levels of some 4-ring and all 5- & 6- ring PAHs in both the local and Czech samples were consistent with published results from investigations employing PAH-specific air samplers. This work strongly suggests that assessment of particle-bound 5- & 6-ring PAHs from archived PM2.5 filters is quantitatively robust. The assay may also be useful for selected 4-ring compounds, notably chrysene and benzo(a)anthracene, if PM2.5 filters are stored under refrigeration.
The research has been subjected to (EPA) Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.