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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 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 59 samples taken in and around ground zero from October 25 through October 27. 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 1383, with 28 samples (27 of these were collected prior to September 30 and one on October 9) above the standard.
Four air samples taken in New Jersey on October 24 showed results less than the school re-entry standard. This brings the total number of samples collected and analyzed in New Jersey to 153, with zero above the standard.
Staten Island Landfill:
Air (Asbestos) - Thirteen samples were collected on October 26 . One sample, at Location 14 (barge station) exceeded the school re-entry standard. All of the remaining samples showed results less than the school re-entry standard.
Particulate Monitoring - Samples collected on October 26 using portable monitors showed an increase in concentrations along the northeast and eastern edge of the landfill. These concentrations decreased on October 27 and decreased further on October 28.
Ambient Air Sampling:
Dioxin - Ten samples were collected on October 11 and analyzed for dioxin/furans. Three of the samples (Location 3 - SW of WTC Building #5, Location A - at W. Broadway and Barclay and Location B - Church and Dey St.) showed results above the level at which EPA would take some type of action to reduce people's exposure. This action guideline is based on a 30-year exposure. However, none of the samples were above the EPA action guideline adjusted to a one-year exposure. These levels do not pose a short-term health affect, but should be monitored if they persist for a longer period of time.
VOCs - Sampling for volatile organic compounds (VOCs) was conducted October 26 through October 28 in the direct area of the debris pile at ground zero. On each of the three days, benzene exceeded the OSHA time-weighted permissible exposure level at two locations. On October 26 five samples were collected and analyzed for Freon-22 (chlorodiflouromethane), Freon-22 was not detected in these samples. Freon-22 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, both at ground level, in samples collected on October 27 and within the debris pile of the North Tower on October 28, also at ground level. Levels detected were well below the NIOSH recommended exposure limit of 1,000 parts per million (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 26 through October 27 at Pace University, the Borough of Manhattan Community College, the U.S. Coast Guard building located in Battery Park and Albany Street at Battery Park City. All 24-hour average values 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 that indicates when air quality is unhealthy for sensitive populations (e.g., those with respiratory illnesses).
Direct Air Readings - Using portable monitors, direct air readings were taken in and around ground zero on October 27 and October 28. Several carbon monoxide readings were detected above the National Ambient Air Quality Standard (NAAQS) 8-hour average of 9 ppm during the early afternoon on October 27 and during the late morning on October 28; however the readings were below the NAAQS 1-hour average of 35 ppm and the OSHA permissible level of 50 ppm.
Silicates - Ten samples were collected on October 11 and analyzed for silicates. No silicates were detected in these samples. An additional 10 samples were collected on October 18; silicates were either not detected or were detected at levels below the NIOSH Recommended Exposure Limit (REL) time-weighted average of 0.05 mg/m3.
Direct Air Readings - Using portable monitors, direct air readings were taken in and around ground zero on October 27 and October 28. Several carbon monoxide readings were detected above the NAAQS 8-hour average of 9 ppm, during the early afternoon on October 27 and during the late morning on October 28. The readings were below the NAAQS 1-hour average of 35 ppm and the OSHA permissible level of 50 ppm.
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