Chain of custody form, 21 West Street, Nov 2001

NYC 9/11 Public Portal Document FEB-28-2002 THU 11 15 AM CLOSINGS 0 ROSE FAX NO. 212 210 6724 P. 29/42

lce Asr5ot;lates JLG Proiect# 01-2089 ,

G ttober 6, 2001 page 2 AIr SarnpIinaAnahl8le and lrQedure Introduction Air sampling is defined as the prucaass of measuring the filter content of a known volume of air entrained on a filter membrane over a specified period of time. Each sample is cross-referenced by field designation and a JLC lab Internal code to ensure proper, consistent handling through a chain of custody. Sample preparation takes place within an HEPA filter clean bench to avoid any possible contamination.

Methodology "Pest procedures for these samples conform to the National Institute of Occupational Safety and {-health (NIOSI-1) standards.

•? Air sampling was conducted at a level approximating the breathing zone of persons anticipated to be present in the area during normal operations. Samples collected should represent the area's •Y typical airborne fiber concentration.

All samples were collected on fully exposed 25 millimeter, 0.8 mtcrorneter(pm)cellulose ester membrane air sampling cassettes with conductive cowl.

Analytical Procedures on A section of the filter approximating twerity-five percent of the total filter was removed and placed a pre-cleaned microscope slide and then exposed to approximately 250 microliter (VI) of acetone vapor. A 3,0 •-3.5 pi drop of triacetin applied and #1.5 single was a clean cover slip was placed

analysis to

until allowed clarity

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Results

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