VOC sampling locations table for Ground Zero area, Jan 2002

NYC 9/11 Public Portal Document

During the days following the September 11 events, substantial efforts were made to quickly augment existing PM monitoring capabilities by the addition of PM sampling sites immediately around the WTC Ground Zero work zone and in surrounding lower Manhattan neighborhoods. Of particular note, staff from EPA’s National Exposure Research Laboratory (NERL) worked with EPA Region 2 colleagues to set up PM samplers at three surface sites triangulating the WTC Groimd Zero work zone perimeter, as shown in Figure 2 (lettered sites A, C, and K). Site A was located at Barclay and W. Broadway just north of Ground Zero, Site C at Liberty and Trinity to the southeast of Ground Zero, and Site K at Albany and West to the southwest of Ground Zero. In addition to these surface sites, ORD PM sampling was initiated at the 16* floor level in EPA Region 2 facilities in the Federal Building at 290 Broadway about six or seven blocks northeast of the WTC. These sites are noted in Table 1 of Appendix B, as EPA Response Team Lettered Sites at Locations A, C, and K and Site #16 under EPA/ORD Numbered Air Monitoring Stations. By October 2, the U.S. EPA Region 2 and EPA OAQPS, along with New York State Department of Environmental Conservation (NYSDEC) personnel, set up PM instruments at Chambers Street, Park Row, and the Coast Guard Building at the Battery, which along with the existing monitors at Canal St., surrounded Ground Zero a few blocks farther out than the ORD sites.

Measurements of ambient air PM2 5 elemental composition were made by ORD staff (Vette et al., 2002) at the three ORD surface sites (A, C, and K), using saturation samplers (SS), and on the 16* floor of the 290 Broadway Federal Building, using a modified dichotomous versatile air pollutant sampler (VAPS). The VAPS also collected PMio.2.5 samples. Only the battery-powered saturation samplers could be operated within the WTC perimeter because power outages precluded operation of conventional samplers, such as EPA Federal Reference Method (FRM) samplers in use at preexisting NY State-operated PM monitoring sites. Although the SS has been shown (Hill, et al., 1999; also see http://www.airmetrics.eom/products/studies/l.html) to achieve accuracy within 6-10% compared to PM2 5 FRM measurements at concentrations typically found in ambient air, uncertainty in measured PM2 5 concentrations increase as ambient concentrations increase, especially above 100 pg/m’ (24-h average). Indeed, even the FRM is subject to increasing uncertainties at high PM2 5 levels. However, the general characterization of air quality used for EPA’s Air Quality Index (AQI) should be largely unaffected. The use of these samplers (SS) allowed for x-ray flourescent (XRF) analyses of the elemental composition of aerosol samplers. Such XRF analyses were performed on filters collected from September 21, 2001, to January 31,2002. These samples were collected on an almost daily basis for sampling periods of about 22 hours per day. In addition to the VAPS sampler, high time-resolution measurements of light scattering by particles (which is related approximately to the concentration of fine PM) and light extinction (which is related to the concentrations of black carbon and to complex organic compounds such as PAHs) were also made. The main focus of discussion here with regard to EPA/ORD results is on findings from filter-derived PM mass and elemental composition measurements.

The ORD PM monitoring sites triangulating the WTC Ground Zero perimeter were placed so as to allow: (a) continuous tracking of PM2.5 emissions from Ground Zero, useful for detecting any extraordinarily high-level PM2.5 exposures to rescue/recovery workers and others operating within or immediately around Ground Zero; and (b) the determination of the physical/chemical composition of WTC-generated PM emissions from the smoldering fires or

DRAFT-DO NOT QUOTE OR CITE 26 October 2002

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