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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 120 samples taken in and around ground zero from October 29 through November 1. 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 1605, with 28 samples above the standard (27 of these were collected prior to September 30 and one on October 9).
Staten Island Landfill:
Air (Asbestos) - Twenty-nine samples were collected on October 30 and October 31. All the samples showed results less than the school re-entry standard. Seven samples collected on October 30 were not analyzed due to filter overloading; these samplers were located around the sifting and wash operations areas. One location on October 31 experienced sampler pump failure deeming the results invalid. Eighteen additional samples were collected from October 31 through November 1. All samples showed results less than the school re-entry standard. One location again experienced sampler pump failure deeming the results invalid.
Ambient Air Sampling:
Asbestos - Additional asbestos monitors have been placed at the eight particulate matter monitoring stations located at Pace University, Borough of Manhattan Community College, the Coast Guard building in Battery Park, Public School (P.S.) 154 (33 East 135th St., Bronx), Intermediate School 143 (511 W. 182nd St., Manhattan), P.S. 274 (800 Bushwick Ave, Brooklyn), P.S. 44 (80 Maple Parkway, Staten Island), and P.S.199 (3290 48th St., Queens). On October 29, seven asbestos samples were collected and analyzed from these locations; no samples were collected from Intermediate School 143. All the results showed no exceedances of the AHERA re-entry standard.
VOCs - Sampling for VOCs was conducted on November 1 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 PEL of 1 part per million (ppm) at one location (South Tower) at ground level on the debris pile in the plume. One of the two samples (North Park Pier) did not detect any benzene levels above the detection limit of 20 parts per billion by volume (ppbv). Chlorodifluoromethane (Freon-22) was detected and confirmed in the North Tower debris pile (960 ppbv) at ground level, but was well below the NIOSH recommended exposure limit of 1000 ppm.
PM 2.5 - Monitoring for fine particulate matter (particles less than 2.5 micrometers in diameter) was conducted October 31 and November 1 at Pace University, Borough of Manhattan Community College, and the U.S. Coast Guard building located in Battery Park. All 24-hour averages were below the National Ambient Air Quality Standard (NAAQS) of 65 microgram per cubic meter (ug/m3) for all stations. These results were also less than 40 ug/m3, a level on the EPA Air Quality Index, which would indicate that air quality is unhealthy for sensitive populations (e.g., those with respiratory illnesses).
Particulate Monitoring - EPA used portable monitors to collect samples on November 1 in the following areas, which are also the locations of fixed air monitors: 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.
Direct Air Readings - Direct readings taken on November 1 showed nothing of significance. No readings were noted above the NAAQS (8-hour average) of 9 ppm for carbon monoxide.
U.S. Government Website