NYC-WTC_000204914

NYC 9/11 Public Portal Document

[i Patrice Armstrong - Bldg27.wpd

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i Summary of Asbestos Sampling Results Page 2 of 2 I Address: 100 John Street Date sampled; Dec 3, 2001

Air samples

Airborne fibers as determined by Phased Contrast Microscopy (PCM): An air sample is collected by pulling air tlirough a filter. The filter catches fibers and is sent to a laboratory to detennine what types of fibers were in the air. Phase contrast microscopy identifies fibers based on size and shape, but not mineral composition. Therefore, the fibers seen by PCM include asbestos fibers as well as other fibers, such as textiles, fiberglass, cellulose, which might be present in your home. By coiuiting all fibers, we are being more protective of your health when we compare this to our screening value for asbestos fibers.

Area Sampled Outside Common Residence 1 Residence 2 Sample Numbers A-O-27 A-C-27 A-Rl-27 A-R2-27 Concentration of Fibers in Air <001 <001 <001 <001 at this location Concentration of Fibers in Air <001 to .001 <001 to .002 <.001 to .002 <.001 to .002 I at background locations Screening Value .01 f/cc .01 r/cc .01 Pcc .01 f/cc

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