Chain of custody form, 21 West Street, Nov 2001

NYC 9/11 Public Portal Document FEB-28-2002 THU 1106 AM CLOSINGS 0 ROSE FAX NO. 212 210 6724 P. 14/42

Rose Associates Inc. JLC Project # 01-2089004 -November 8, 2001 page 2 Air Samo_iIng na'ysis sand Prpcedure Introduction utent of a known volume of air Air sampling is defined as the process of measuring the filter eu is cross-referenced by entrained on a Miter membrane over a specified period of time. Each sample proper, consistent handling through a chain field designation and a JLC lab internal code to ensure clean bench to avoid any possible of custody. Sarnple preparation takes place within an HEPA filter contamination.

Methodology institute of C_)c:cupational Safety and J ast procedures for these samples conform to the National Health (NIOSH) standards. of persons anticipated to Air'sampling was conducted at a level approximating the breathing zone collected should represent the area's be present In the area during normal operations. Samples typipal airborne fiber concentration. 0,8 micrometer (pm) cellulose ester All samples were collected on fully exposed 25 millimeter, membrane air sampling cassettes with conductive cowl.

Analytical Procedures total (ilterwas removed and placed on A section of the filter approximating twenty-five percent of the microliter (ttl) of acetone a pre-cleaned microscope slide and then exposed to approximately 250 clean #1.5 cover slip was placed vapor. A single 3.0 - 3.5 µl drop of triacetin was applied and a heater until clarity allowed analysis to upon the filter. The prepared slide was then heated on a slide be conducted. with NIOSH 7400 Analysis was accomplished utilizina a Phase Contrast Microscope in accordance ;f; method, counting rule "A.'

Phase Contrast Microscopy Contrast Microscope, (PCM) JLC Eravironrnental's laboratory uses an Olympus RH-PC Phase dissolving the filter equipped with a Walton-Beckett Graticule. Samples were analyzed by first with PCM at 400x through a chemical process (described above) and then counting the fibers background, n magnification. stist':~reases the ht contrast een the object l fibers. Normal abiilty to see ly, 100 r~6aple fields or 100 thus enhancingPiemicroscaop fihors c ro counted, whichever nr.nurs first.

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

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