NYC-WTC_000207776

NYC 9/11 Public Portal Document

104 East 25th St,, 10th Fl New York, New York 10010 www.atc-enviro.com 212.353.8280 Fax 212.353.8306 ASSOCIATES INC.

September 6, 2002

Mr. Bernard P. Orlan Director, Environmental Health & Safety New York City Department of Education 28-11 Queens Plaza North Long Island City, NY 11101-4008

Re: Indoor Air Quality Assessment P.S. 42M 71 Hester Street New York, New York ATC Project No. 15-19125-0342

Dear Mr. Orlan:

ATC Associates Inc. (ATC) is pleased to provide this report of indoor air quality (lAQ) measurements collected on September 4, 2002 at the referenced school. The New York City Department of Education (DOE) requested these measurements as part of a program to verify that acceptable indoor air quality is being maintained.

SCOPE OF WORK

ATC conducted this evaluation to assess the basic parameters of temperature, relative humidity, carbon dioxide (CO,) and carbon monoxide (CO).

Total volatile organic compounds (TVOCs) and respirable particulates were also measured.

Mariana Medinets, Environmental Technician of ATC’s New York City office, conducted the assessment. ATC’s findings are based on a visual inspection, real-time environmental measurements and conditions present in the school at the time of the assessment.

ATC measured temperature, relative humidity, CO, and CO with a Q-Trak® Model 8551, manufactured by TSI, Inc.

ATC measured concentrations of respirable particulates (PM2.5) with a Dust-Trak® Aerosol Monitor Model 8520, manufactured by TSI, Inc.

ATC measured concentrations of TVOCs using a RAE Systems, Inc. MiniRAE® photoionization detector (PID).

The assessment was performed consistent with generally accepted indoor air quality assessment practices. As with all such assessments, there were inherent limitations created by constraints of time, operational and work practice variability, variations in indoor air quality parameters and sampling and analytical accuracy.

CITY_21MC100_003016080

NYC-WTC_000207776