80 JOHN STREET; Block: 68 Lot: 33 BIN: 1001115 19-25 Gold Street, 25-27 Platt Street

NYC 9/11 Public Portal Document

WSA Management JLC Project # 01-2171 October 29, 2001 page 2 Air Sampling Analysis and Procedure Introduction sampling is defined as the process of measuring the filter content of a known volume of air Air period of time. Each sample is cross-referenced by entrained on a filter membrane over a specified through a chain to ensure proper, consistent handling field designation and a JLC lab internal code within possible Sample preparation takes place an HEPA filter clean bench to avoid any of custody. contamination.

Methodology the National Institute of Occupational Safety and Test procedures for these samples conform to Health (NIOSH) standards. approximating the breathing zone of persons anticipated to Air sampling was conducted at a level Samples collected should represent the area's be present in the area during normal operations. typical airborne fiber concentration. millimeter, 0.8 micrometer (Nm) cellulose ester All samples were collected on fully exposed 25 membrane air sampling cassettes with conductive cowl.

Analytical Procedures of the filter approximating twenty-five percent of the total filter was removed and placed on A section exposed to approximately 250 microliter (pl) of acetone a pre-cleaned microscope slide and then and a clean 1.5 cover sli was placed vapor. A single 3.0 - 3.5 NI drop of iacetin was da slide heate#until clarity alplwed analysis to upon the filter. The prepared slide was then heated on be conducted. Contrast Microscope in accordance with NIOSH 7400 Analysis was accomplished utilizing a Phase method, counting rule "A."

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

Analytical Results the results of the analysis of the samples. The The "Summary of Analytical Results" represents mers/cubic cenmet of air. If final tests PCM limit of reliable quantification is lessthan o.oi

(f/cetested. do not meet these requirements, the entire site ust be re-cleanedand r

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