NYC-WTC_000202336

NYC 9/11 Public Portal Document

<Satc 104 East 25th St, 10th Fl New York, New York 10010 www.atc-enviro.com 212.353.8280 Fax 212,353.8306 A S S 0 C I A T E S INC.

September 19, 2002

Mr. Bernard P. Orlan Director, Environmental Health & Safety New York City Department of Education 28-11 Queens Plaza North Long Island City, NY 11101

Re: Air Sampling for Silica High School for Leadership and Public Service (M894) 90 Trinity Place New York, New York ATC Project No. 1549125-0290.'^^^/'

Dear Mr. Orlan: i ATC Associates, Inc. (ATC) is pleased to provide this report of air sampling for silica- containing dust conducted on September 5, 2002, at the referenced school. The New York City Department of Education (DOE) requested this sampling to verify that acceptable indoor air quality is being maintained.

SCOPE OF WORK

ATC collected three (3) samples for respirable particulates using pre-weighed 37mm PVC filters connected to size-selective cyclones to remove the larger (non-respirable) particles prior to deposition on the filters. All three samples were collected indoors. The samples, plus one blank filter, were sent to PSC Analytical Services, Inc., an American Industrial Hygiene Association accredited laboratory in Reading, PA. Analysis was performed by x-ray diffraction according to OSHA Method 142. A copy of the analytical laboratory report is attached.

Tenzin Namgyal, Industrial Hygienist of ATC’s New York City office, collected the samples consistent with generally accepted industrial hygiene assessment practices. As with all such assessments, there were inherent limitations created by constraints of time, operational and work practice variability, variations in air contaminant concentrations and sampling and analytical accuracy. The results represent conditions on the date the samples were collected.

CITY_21MC100_003272209

NYC-WTC_000202336