NYC-WTC_000213100

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan June 3, 2002 Indoor Air Quality Measurements Page 3 Stuyvesant High School (M477) __________ ATC Project 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 I. Readings began at 8:00 A.M. and concluded after 12:45 P.M.

Temperature

Indoor dry bulb temperature measurements ranged from 69.6 °F to 78.6 °F. Ninety (90) of the indoor measurements were below 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 was 70.3 to 78.4 °F.

Relative Humidity

The relative humidity indoors ranged from 58.6 percent to 69,9 percent. One hundred and twelve (112) of the indoor measurements for relative humidity were above the ASHRAE- recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity levels were 78.2 and 81.3 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 425 ppm to 1196 ppm. Twenty-three (23) 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 385 ppm and 391 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1091 ppm (background level + 700 ppm). 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.

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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 ranged were 1 ppm.

Respirable Particulates (Pl^2.5)

Respirable particulate concentrations* indoors ranged between 25 p.g/m3 to 45 pg/m^ with an average of approximately 33 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. Four of the indoor measurements were above the USEPA recommendation of 40 pg/m3 for sensitive individuals and children. The outdoor respirable particulate concentrations were 71 and 79 pg/m^.

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NYC-WTC_000213102