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MEASURING AIRBORNE PAHS FROM THE NEW YORK WORLD TRADE CENTER DISASTER
Citation:
Pleil, J D. MEASURING AIRBORNE PAHS FROM THE NEW YORK WORLD TRADE CENTER DISASTER. Presented at School of Public Health, Chapel Hill, NC, November 12, 2003.
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:
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in ambient air, are suspected human carcinogens, and have been linked to genotoxic and mutagenic effects. Although there are no specific monitoring programs for PAHs in ambient air in the United States, there is a national network of about 1,100 samplers for assaying ambient particulate matter less than 2.5 ?m aerodynamic diameter (PM2.5). This work utilizes archived filter samples from the PM2.5 program for retrospective assay of particle-bound PAH concentrations in ambient air without the forethought of having deployed specialty PAH samplers.
Specifically, Teflon filter PM2.5 samples were collected by U.S. EPA in the aftermath of the New York World Trade Center (WTC) disaster for nondestructive assessment of the fine particle concentrations; these were subsequently archived. The samples had been collected daily at three WTC fenceline sites at "ground zero" and one site 5 blocks away from September 23, 2001 to March 30, 2002. We have assayed a subset (235) of these samples for certain particle-bound PAHs and have estimated their ambient concentrations spatially and as a function of time since September 11, 2001. The data exhibit large within-day and between-day concentration variability with a statistically significant trend decreasing to background over a period of about 6 months. We estimated an initial 8-fold PAH increase at ground zero during the first week (mean value 0.9 ng/m3 for 5- and 6-ring PAHs) after the disaster with a half-life of 64 days; the single site further away from ground zero shows a lower, less significant trend.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.