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Daily Environmental Monitoring Summary

Saturday - Thursday, December 22-27, 2001

The U.S. Environmental Protection Agency (EPA) and other federal, state and local agencies have collected extensive environmental monitoring data from the World Trade Center site and nearby areas in Manhattan, Brooklyn and New Jersey. Since September 11, EPA has taken samples of the air, dust, water, river sediments and drinking water and analyzed them for the presence of pollutants that might pose a health risk to response workers at the World Trade Center site and the public. The samples are evaluated against a variety of benchmarks, standards and guidelines established to protect public health under various conditions. EPA is collecting data from more than 20 fixed air monitors in and around ground zero and additional monitors in the Bronx, Brooklyn, Queens and Staten Island. The Agency is also using portable sampling equipment to collect data from a range of locations.

Results as of 7:00 a.m. on 12/28

Staten Island Landfill:
Air (Particulates) - EPA used portable monitors to collect samples of particulates on December 19, 22 and 26 at the Staten Island Landfill. No significant readings reported.

Ambient Air Samples - Lower Manhattan:

PM 2.5 - Monitoring for fine particulate matter (particles less than 2.5 micrometers in diameter) was conducted from December 17 through 20 at Pace University, Borough of Manhattan Community College, the Coast Guard building in Battery Park and on Wall Street. All 24-hour averages were below the National Ambient Air Quality Standard (NAAQS) of 65 ug/m3 for all stations. These results were also less than 40 ug/m3, a level on the EPA Air Quality Index indicating that air quality is unhealthy for sensitive populations (e.g., those with respiratory illnesses).

PM10 - Monitoring for particulate matter (particles less than 10 micrometers in diameter) was conducted from December 17 through 20 at a location on Wall Street. All 24-hour average values were below the National Ambient Air Quality Standard of 150 ug/m3.

Particulate Monitoring - EPA used portable monitors to collect samples from December 19 through December 23 and on December 26 in the following locations: L (north east side of Stuyvesant High School); N (south side of Pier 25); and R (north west side of Stuyvesant High School). All readings were below the OSHA time-weighted permissible exposure limit for particulates.

VOCs - Sampling for volatile organic compounds (VOCs) was conducted from December 19 to 23 and on December 26 in the direct area of the debris pile at ground zero. To protect workers at the work site, EPA takes grab samples of VOCs where smoke plumes have been sighted. The results are snapshots of the levels at a moment in time. OSHA's protective standards set a permissible exposure limit (PEL) averaged over an 8-hour day. Benzene exceeded the OSHA standard on Dec. 20 and 22 on the debris pile at the North Tower and on December 23 and 26 at the North Tower debris pile. Fourteen of twenty other samples taken at EPA's Wash Tent (West St. and Murray), Austin Tobin Plaza and in the debris area at ground level showed no detectable levels of benzene.

Direct Air Readings - EPA did air monitoring in and around ground zero for a number of compounds from December 19 through 24. No significant readings were found December 20 through 24. On December 19, nothing of significance was found in the routine monitoring. EPA did additional monitoring on December 19, analyzing air samples from in and around ground zero for hexamethylene diisocyanate (HDI), methylene bis(4-phenyl isocyanate) (MDI) and toluene-2,4-diisocyanate (TDI). Low levels of HDI, MDI and TDI were identified at four locations: North Tower, South Tower, Vista Hotel and Church and Dey. All levels were below the OSHA permissible exposure limits.

Latest Available Daily Environmental Monitoring Summary

EPA information about the events of September 11

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