NYC-WTC_000203528

NYC 9/11 Public Portal Document

104 East 25th St., 10th Floor New York, New York 10010 www.atc-enviro.com 212 353.8280 Fax 212.353.8306 ASSOCIATES INC.

December 3, 2001

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

Re: Air Sampling for Hydrocarbons, Mercury, Metals and Silica P. S. 234M ATC Project No. 15-19125-0279

Dear Mr, Ori an;

ATC Associates, Inc. (ATC) is pleased to provide this report of air sampling for hydrocarbons, mercury, metals and silica conducted on November 13, 2002, at the referenced school. The New York City Department of Education (DOE) requested this sampling to verify that acceptable air quality is being maintained in the school building.

ATC collected four (4) samples each for hydrocarbon compounds (HC), mercury, metals and seven (7) samples for silica at specified locations. All samples were collected for ten (10) hours.

SAMPLING METHODOLOGY

For the HC, ATC used activated coconut shell charcoal tubes connected to battery- powered sampling pumps at a flow rate of 0.2 liters per minute (L/M). Metal samples were collected using mixed cellulose ester filters and pumps set to draw 2.0 L/M. Mercury vapor samples were collected using Carulite® (Hydrar) tubes connected to battery-powered sampling pumps calibrated to collect 0.2 L/M. Respirable dust (silica) samples were collected 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 of the silica samples were collected indoors. All sampling pumps were calibrated before and after each sampling period. Three (3) samples for HC, mercury and metals were collected inside the building and one (1) was collected outdoors. One blank tube each for HC and mercuiy were also submitted. Two blank MCE filters for metals were submitted and one blank pre-weighted PVC filter was submitted.

METHOD OF ANALYSIS

All samples were sent to PSC Analytical Services, Inc., an American Industrial Hygiene Association-accredited laboratory in Reading, PA.

CITY_21MC100_003058456

NYC-WTC_000203528