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NYC 9/11 Public Portal Document

WSA Management JLC Project # 01-2214 November 16, 2001 page 2 Air Sampling Analysis and Procedure Introduction filter r defined as the process of measuring Air sampling is period of Each sample is cross-referenced by entrained on a filter membrane over a spec internal code to ensure field designation and a JLC lab within HEPA filter clean bench to avoid any possible of custody. Sample preparation takes place contamination.

Methodology Institute of Occupational Safety and Test procedures for these samples conform to the National Health (NIOSH) standards.

conducted at a level approximating the breathing zone of persons anticipated to Air sampling was the area's in the area during normal operations. Samples collected should represent be present typical airborne fiber concentration. exposed 25millimeter, 0.8 micrometer (pm) cellulose ester All samples were collected on fully hconductive cowl. membrane air sampling cassettes w

Analytical Procedures on filter approximating twenty-five percent of the total filter A section of the exposed to approximately 250 microliter of acetone a pre-cleaned microscope slide and then e p (u)

cover slip was placed A single 3.0 - 3.5 pl drop of triacetin was applied and a clean #1.5 analysis to vapor. allowed filter. The prepared slide was then heated on a slide heater until clarity upon the be conducted. with NIOSH 7400 was accomplished utilizing a Phase Contrast Microscope in accordance Analysis method, counting rule A.

Phase Contrast Microscopy Microscope, (PCM) an Olympus BH-PC Phase Contrast JLC Environmental's laboratory uses Samples were analyzed by first dissolving the filter equipped with a Walton-Beckett Graticule. at 400x a chemical process (described above) and then counting the fibers with PCM background, through contrast between the object and the magnification. Phase contrast increases the light to see fibers. Normally, 100 microscopic fields or 100 thus enhancing the microscopists abilirst fibers are counted, whichever occurs

Analytical Results The of Analytical Results" represents the results of the analysis the samples. The "Summary mpl If final tests centimeter (f/cc) air. PCM limit of reliable quantification is less than 0.01 fibers/cubic and re -tested. the entire work site must be re-cleaned do not meet these requirements,

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