NYC-WTC_000196909

NYC 9/11 Public Portal Document

i 104 East 2

ASSOCIATES TC INC. New York, New York www.atc-envir 212-352 Fax 212.355

January 29, 2002

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

Re: Outdoor Respirable ParticuiateVir Monitoring Various Manhattan Locations \ ATC Project No. 15-19125-0279^

Dear Mr. Orian;

ATC Associates Inc. (ATC) is pleased to provide this report of the results of real­ time air monitoring of respirable particulates conducted on January 29, 2002, at numerous locations. The New York City Board of Education (BOE) requested this monitoring to obtain comparison data for lower Manhattan schools.

SCOPE OF WORK

Darnell Nehlich, Environmental Technician from ATC’s New York City office, conducted the monitoring. ATC’s findings are based on real-time environmental measurements. Real-time readings of respirable particulates PM2.5) were collected only from outdoors.

ATC recorded concentrations of respirable particulates with a Dust Trak® Aerosol Monitor Model 8520, manufactured by TSI, Inc.

The assessment was performed consistent with generally accepted 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 air quality parameters, and sampling and analytical accuracy. The results of the sampling represent conditions found on the date of the survey and may not represent conditions found at other times.

EVALUATION CRITERIA

Table 1 lists the target guideline for the parameter that ATC evaluated during this investigation.

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