Asbestos sampling summary, 250 South End Avenue, Nov 2001

NYC 9/11 Public Portal Document

Page l of -1 Summary of Asbestos Sampling Results 250 South End Avenue, New York, N.Y., 10280 Date sampled: November 14, 2001

Air samples were collected at four locations and dust samples were collected at five locations at your building. Air and dust samples were collected inside two private residences, an indoor common area (e.g., a lobby or hallway), and a nearby outdoor area. An additional dust sample was collected from a window sill from another private residence. (See tables below for sampling results).

Air samples were collected using vacuum pumps to draw air past a filter that was suspended at the height of a person's breathing level. Outdoor dust and debris samples were collected by placing visible material in a container. Indoor dust and debris samples were collected on a filter by vacuuming surfaces. The collected material was weighed, viewed under a microscope, and/or chemically processed to determine the types and quantities of substances present. The materials are being analyzed for fibers such as asbestos, fiberglass, synthetics (e.g. man-made materials such as nylon and polyester), cellulose (e.g. cotton, paper), silica, and for other minerals and small particles.

ASBESTOS AIR TEST RESULTS

The air samples tested from outside, in the common area and an occupied residence of your building were taken during normal daily activity. The air sample from the unoccupied apartment was taken after the dust in the apartment was aggressively "stirred up" to ensure that an accurate sample of particles would be present. All air samples were examined in a laboratory for fibers using the Phase Contrast Microscopy (PCM) method.

Airborne fibers as determined by PCM analysis: An air sample is collected by pulling air through a filter. The filter catches fibers and is sent to a laboratory to determine the number of fibers in the air. Phase contrast microscopy identifies fibers based on size and shape, but not the specific type of fiber. Therefore, the fibers seen by PCM include asbestos fibers as well as other fibers, such as textiles, fiberglass and cellulose which might be present in your home. The PCM analysis assumes that all fibers present were asbestos. Therefore, less hazardous fibers that may have been present, such as textiles or fiberglass, are counted along with the asbestos fibers, and the total fiber count is then compared to the asbestos standard. If the results were above 0.003 f/cc using the PCM methodology, additional analysis was performed to determine whether any of the fibers were asbestos. This additional analysis was done for the common area air sample.

Results of all of the air samples taken from your building were below the standard set for indoor air quality - 0.01 fibers per cubic centimeter (f/cc). With the exception of one sample, the levels of fibers found were comparable to the air results from buildings located above 59`h Street, which are not expected to have been impacted by WTC materials. In the homes above 59`h Street, levels of fibers found in the air ranged from less than 0.001 f/cc to 0.003 flcc. One air sample (0.005 f/cc) was slightly above the levels found in the comparison buildings, however, analysis of this air sample by transmission electron microscopy (TEM), shows these fibers were not asbestos (see below for further details).

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