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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 and New Jersey:
Asbestos - EPA analyzed 40 samples taken in and around ground zero from October 24 through October 25. All samples showed results less than 70 structures per millimeter squared, 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 1324, with 28 samples (27 of these were collected prior to September 30 and one on October 9) above the standard. The total number of samples now reflects the results from the supplemental asbestos monitoring stations in lower Manhattan reported in the 10/25 summary.
Three air samples taken in New Jersey on October 23 showed results less than the school re-entry standard. This brings the total number of samples collected and analyzed in New Jersey to 149, with zero above the standard.
Staten Island Landfill:
Air (Asbestos) - 38 samples were collected October 24 through October 25 . One sample, at Location 12 A (indoor wash station) exceeded the school re-entry standard, this incident is being investigated further. All of the remaining samples showed results less than the school re-entry standard.
Particulate Monitoring - Samples collected on October 25 using portable monitors showed no significant readings, samples could not be collected on October 23 and 24 due to weather conditions.
Ambient Air Sampling:
VOCs - Nine samples for volatile organic compounds (VOCs) were collected over approximately a 24-hour period September 27 through September 28 at the following locations: Location A (Barclay & West St), Location B (Church & Dey St.), Location C1 (Liberty & Broadway), Location E (Liberty & South End), Location F (Vesey and West St.), Location P (Albany & South End), Location R (north west side of Stuyvesant High School), and Location S (Rector and South End). These locations are near or just beyond the perimeter of the debris pile. VOCs were either not detected or detected at levels below EPA removal action guidelines which are based on a thirty-year exposure duration. This demonstrates that ambient VOC concentrations at the perimeter are significantly lower than levels of VOCs detected using grab samples on the debris pile in the plume.
Sampling for volatile organic compounds (VOCs) was conducted on October 25 in the direct area of the debris pile at ground zero. Benzene exceeded the OSHA time-weighted average permissible level at two locations. Freon-22 (chlorodiflouromethane) was detected and confirmed in samples collected from within the debris pile of the North Tower and in the debris pile of the South Tower at ground level. Levels detected were well below the NIOSH recommended exposure limit of 1,000 ppm. EPA is working with the local agencies and health and safety officers working at ground zero to closely monitor this situation so that workers can take appropriate precautions.
PM 2.5 - Monitoring for fine particulate matter (particles less than 2.5 micrometers in diameter) was conducted October 23 through October 25 at Pace University, the Borough of Manhattan Community College, and the U.S. Coast Guard building located in Battery Park. All 24-hour average values were below the National Ambient Air Quality Standards (65 ug/m3) for all stations. These results were also less than 40 ug/m3, an EPA air quality index which would indicate the air quality is unhealthy for sensitive populations (e.g., those with respiratory illnesses).
Particulate Monitoring - EPA used portable monitors to collect samples on October 25 in the following areas, which are also the locations of Fixed Air Monitors: L (north east side of Stuyvesant High), R (north west side of Stuyvesant High School), and N (South side of Pier 25). All readings were all below the OSHA time-weighted average permissible level for particulates.
Direct Air Readings - Using portable monitors, direct air readings were taken in and around ground zero on October 25. Several carbon monoxide readings were detected above the National Ambient Air Quality Standard (NAAQS) 8-hour average of 9 ppm, however the readings were below the NAAQS 1-hour average of 35 ppm and the OSHA permissible level of 50 ppm.
U.S. Government Website