VOC sampling locations table for Ground Zero area, Jan 2002

NYC 9/11 Public Portal Document

Air Concentrations During the First Several Days After September 11: An event such as September 11 demonstrates that the greatest environmental impacts occur in the first 24 to 48 hours and in areas close to the site. Difficulties associated with site access and security, power supply sources, equipment availability and analytical capacity hindered efforts by EPA and the New York State Department of Environmental Conservation (NYSDEC) to put air monitors in place immediately after the attack. While dust samples were collected for analysis on September 11, the first air samples of some of the critical contaminants were not taken until September 14, such as asbestos, while other contaminants were not sampled until September 23, such as dioxin. Rapid initiation of monitoring will allow the measurement of air concentrations that can be very important for evaluation of inhalation exposures and potential short and long-term human health impacts. An examination of the concentrations measured during September show that the highest concentrations were the ones taken closest in time to September 11, closest in proximity to Ground Zero, and in the downwind direction. For example, five measurements of dioxin TEQs were over 100 pg TEQ/m’ (all others were under 100 pg TEQ/m^), and these were the first measurements in the three nearest downwind monitors: the first 3 measurements in the WTC Building 5 monitor on September 23 (160 pg TEQ/m^), October 2 (170 pg TEQ/m’), and October 4 (170 pg TEQ/m’), the first measurement at the Church and Dey monitor on September 23 (130 pg TEQ/m’), and the first measurement at the Liberty and Broadway monitor on September 23 (100 pg TEQ/m’). While the highest dioxin measurements were found on September within and to the east of Ground Zero, three samplers to the west of Ground Zero showed background levels of dioxins on September 23. Similar trends were seen for other contaminants. It is reasonable to conclude that air concentrations within and very near Ground Zero would have been at least at these high levels and probably higher during the first several days after September 11. These areas were in restricted zones, which minimized overall exposures, and exposures were further minimized for individuals who used protective gear and clothing.

Occupational and Indoor Exposures: Extensive data sets are available from OSHA and NIOSH on occupational exposures on the Ground Zero site. Many of these samples were personal air monitors, and as such, are the most appropriate types of samples for evaluating inhalation exposures of workers. The contaminants evaluated in this report and many more are included in these data sets. The vast majority of samples in both data sets were below occupational standards including OSHA PELs and NIOSH RELs. The ATSDR has completed a study of residential apartments (NYCDOHMH/ATSDR, 2002). Testing occurred between November 4 and December 11, and included 57 apartments in lower Manhattan as well as 5 comparison apartments. In all tested apartments (lower Manhattan and comparison), airborne fibers were not detected above background levels in any of the indoor air samples. However, bulk dust samples showed asbestos in 16% of the apartments in Lower Manhattan, and none in the comparison apartments. Also, synthetic vitreous fibers (SVF or fibrous glass) were found in both indoor and outdoor samples in Lower Manhattan. Another study sampling indoor air and dust on September 18 in 2 locations very near Ground Zero found significantly high concentrations of asbestos in both air and dust, but low, background, concentrations of dioxin, PCBs and metals.

DRAFT-DO NOT QUOTE OR CITE 11 October 2002

NYC-WTC_000149092