DEP Air Monitoring Summary Lower Manhattan, Oct 2001

NYC 9/11 Public Portal Document

Air Monitoring in Lower Manhattan •

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Air, Noise and Hazardous Materiais

Ah I'V101ijtOljfl(i err Lower Manhattan DEP monitored the ambient outdoor air for asbestos following the World Trade Center (WTC) disaster. This effort augmented ambient air asbestos sampling performed by the EPA and other state and city agencies. There is currently no outdoor ambient standard for asbestos. The US and NYC standard for asbestos in community and residential buildings is 0.01 fibers/cubic centimeter (f/cc) in indoor air. An indoor area which has had asbestos detected and then removed must show that air samples are at or below the 0.01 f/cc standard before the indoor area can be re-occupied. Although the ambient outdoor air was monitored, DEP used the indoor air standard as a way to characterize the levels of asbestos in the air.

Since the measurement protocol used, phase contrast microscopy (PCM), counts fibers, DEP also conducted an additional analysis for all samples that were above 0.01 f/ee. This measurement protocol is called transmission electron microscopy (TEM) and counts the number of asbestos fibers in the sample. EPA reported their data in "1'EMs, and provides a good explanation ol'the interpretation of the standard that uses this methodology on their 'v cbsilc.

EPA has also recently published the results of two studies related to the WTC disaster: The Toxicological 1'J)',cts v/'1 Tire Yurriculutc Ab hor Derivedfrom the Destruction of the P7urld Trade ('cute^', and Dw l.ehosurc' and human Health Evaluation of Airborne Pollutiotr frunr t/rc I jrld 1 rade Center Disaster. To read both reports, please click lien

Results indicate that, as expected, asbestos was present in some of the debris at the site and in areas very close to the site. Between September 28, 2001 and August 3, 2002, the vast majority of air sampling results outside the security zone were below the standards for asbestos in indoor air.

To view the air monitoring results, click on a sampling location below or on the map (Links will open in a new browser window,:

Sampling Site Location 1 vi i . l;ioiil\v Iv and 19 v Only ;111,1 11 i ii SUcci 00 ,`Tin rt

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