NYC-WTC_000213072

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan May 17,2002 Indoor Air Quality Measurements Page 3 Stuvvesant High School (M477) ATC Proiect No. 15-19125-0246 Real-Time Environmental Measurements

ATC collected one hundred and twenty (120) sets of real-time environmental measurements consisting of one hundred and eighteen (118) in the school building and two (2) outdoors. All ten floors of the school were surveyed. These results are described below.

Field data sheets are found in Attachment 1. Readings began at 8:00 A.M. and concluded after 1:05 P.M.

Temperature

Indoor dry bulb temperature measurements ranged from 68°F to 73.7°F. One hundred and ten (110) of the indoor measurements were below and eight (8) were within the range of 73 to 79°F (at 50 percent relative humidity) recommended by ASHRAE Standard 55-1992 during the mechanical cooling season (summertime conditions). The outdoor temperature range was 65.1 to70.1°F.

Relative Humidity

The relative humidity indoors ranged from 32.8 percent to 41.2 percent. All of the measurements were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort.. The outdoor relative humidity levels were 35.2 and 38.7 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 458 ppm to 1136 ppm. Twelve (12) of the CO2 measurements were above the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The outdoor (background) CO2 concentrations were 396 ppm and 399 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1099 ppm (background level + 700 ppm). The highest reading was taken in room 936 at 12:10 PM with 30 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.

Carbon Monoxide Concentration

Carbon monoxide concentrations indoors ranged from 0 ppm to 1 ppm. These concentrations were below the NPAAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentrations was 1 ppm for both readings.

Respirable Particulates (PM2_$)

Respirable particulate concentrations* indoors ranged between 16 pg/m^ to 27 pg/m^ with an average of approximately 21 pg/m^. None of the indoor measurements 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 recommendation of 40 pg/m3 for sensitive individuals and children. The outdoor respirable particulate concentrations were 40 and 59 pg/m3.

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NYC-WTC_000213074