NYC-WTC_000209425

NYC 9/11 Public Portal Document

Air Monitoring in Lower Manhattan Page 1 of 3

The City of New York

DSP Department of Environmental Protection

Air, Noise and Hazardous Materials AS9t.t.DEc

' Syertst ' Waswwatar Air Monitoring in Lower Manhattan SwsssK '' Aufejsw DEP is monitoring the ambient outdoor air for asbestos. This effort is augmenting ambient air asbestos sampling ■It HaaWat being done 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 die ambient outdoor an is being monitored, DEP is usmg this value as a way to characterize the levels of asbestos in the air. ... ,£te» Since the measurement protocol used, phase contrast microscopy (PCM), counts fibers, DEP is also conductmg an additional analysis for all samples that are above 0.01 f/cc. This measurement protocol is called transmission . .. electron microscopy (TEM) and counts the number of asbestos fibers in the sample. EPA is reporting their data in .... TEMs, and provides a good explanation of the interpretation of the standard that uses this methodology on their wcbsilc. • , ’ Astatiatawih Results indicate that, as expected, asbestos is present in some of the debris at the site and in areas very close to the . * . site. Between September 28,2001 and the present, the vast majority of air sampling results outside the security zone have been below the standards for asbestos in indoor air.

As testing continues, there may be die possibility of occasional short-term increases in levels of asbestos in the air above the residential standard of 0 01 C'cc of air. When the measured level for the outdoor ambient air is above 0 01 fZee, the samples will be analyzed to determine how many of the fibers are actually asbestos fibers.

To view recent air monitoring results, click on a sampling location below or on the map (Links wiii open m a new browser window): MUluformatei'xs Sampling Site Location •pep News- 1 West Broadway and Worth 19 Vesey and West •^9 Street Street Fa 2 Broadway and Worth Street 20 Vesey tietyyeen Chiirch mid I Grecnuich Street z. 3 Duane Street and Tnntbie 20A VeseyandWest Place Broadway 4 Rirer'I erraecand 21 Fulton and Church Chambers,Street Street 5 Chambers and_North End 22 Fullonbetuecn Ayeriue Church and Broadway 6 Greenwich and Chambers 23 Church and [)cy Street 6A West end of Warren Street 24 Liberty Street and SouthJindAyenue 7

8 WarrenStreetanclNorth BndAvenue West Street and Warren Street 8A Rtyer renacej’ark area 25

26

27 l.ibcrly anti Church Street [ iberly and Broadway ./.tov Qatew ay Plaza_Park % <e. between Park Place and Area Wanren Street 9 RiywTenaw and Pail 28 Washington and Place West Cedar Street

http://www.nyc.gov/html/dep/html/airmonit.html 9/24/02

CITY_21MC100_002841063

NYC-WTC_000209425