NYC-WTC_000199187

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan April 12,2002 Indoor Air Quality Assessment Page 4 P. S. 234M ATC Project No. 15-19125-0279

The average PM2.5 concentration for the entire school building was approximately 13 gg/m^. The outdoor respirable particulate concentration ranged from 24 to 35 pg/m^ with an average of 26 pg/m3.

* The measurements made during this assessment were instantaneous readings, the NPAAQS is a 24-hour average.

TVOC Concentration

TVOCs were not detected anywhere inside the building (0.0 ppm). The outdoor TVOC concentration was also 0.0 ppm. OBSERVATIONS

During this assessment, ATC noted the following: • The building was occupied at the time of the assessment; • No smoke odor was detected in the building.

FINDINGS

Based on the real-time measurements, the following findings are presented:

I. Concentrations of CO and TVOCs were below applicable standards and guidelines. 2. One (1) of the indoor measurements was below the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The highest reading was taken in room 380 (1250 ppm) at 2:20 PM with 19 occupants. Levels above the recommended maximum do not indicate a health risk. Carbon dioxide measurements are used as an indicator of available outdoor air. The primary source of CO2 indoors is occupant respiration. 3. Twenty-seven (27) indoor measurements for temperature were above and twenty-four (24) were within the range of 68 to 75 °F (at 50 percent relative humidity) as recommended by ASHRAE Standard 55-1992 during the heating season (wintertime conditions). 4. None of the indoor or outdoor measurements for PM2.5 were above the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter and the USEPA recommended concentration of 40 pg/m^ for sensitive individuals and children. 5. Twenty-seven (27) indoor measurements for temperature were above and twenty-four (24) were within the range of 68 to 75 °F (at 50 percent relative humidity) as recommended by ASHRAE Standard 55-1992 during the heating season (wintertime conditions).

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NYC-WTC_000199190