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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.
Air: Fixed Monitors in New York:
Asbestos - EPA analyzed 87 samples taken in and around ground zero from December 7 through December 9. All samples showed results less than 70 structures per square millimeter, which is the Asbestos Hazard Emergency Response Act (AHERA) standard for allowing children to re-enter school buildings after asbestos removal activities. This brings the total number of air samples collected and analyzed for lower Manhattan to 3,284, with 29 samples above the standard (27 of these were collected prior to September 30, one was collected on October 9 and the other on November 27).
Staten Island Landfill:
Air (Asbestos) - Eighteen air samples collected on December 8 were analyzed for asbestos. All of these samples were below the school re-entry standard.
Air (Particulates) - EPA used portable monitors to collect samples of particulates on December 10 at the Staten Island Landfill. No significant readings reported. No readings were taken on December 9 and December 11 due to weather conditions.
PM 2.5 - Monitoring for fine particulate matter (particles less than 2.5 micrometers in diameter) was conducted on December 10 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 on December 10 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 on December 11 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 on December 11 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. Two of three samples taken at EPA's Wash Tent (West St. and Murray) and Austin Tobin Plaza showed no detectable levels of benzene.
Direct Air Readings - EPA did air monitoring in and around ground zero for a number of compounds on December 10 and December 11. No significant readings were found. Low levels of carbon monoxide were detected. Samples of cyanide compounds hexamethylene diisocyanate (HDI), methylene bis(4-phenyl isocyanate) (MDI) and toluene-2,4-diisocyanate (TDI) were taken at the northwest corner of the North Tower, Austin Tobin Plaza near the barrier of the inner work zone, the southeast corner of the South Tower (30 feet below street level) and the southwestern corner of the inner work zone at West and Liberty. Monitoring found low levels of HDI and TDI. All levels were below OSHA PELs and National Institute of Occupational Safety and Health (NIOSH) recommended exposure limits (REL).
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