NYC-WTC_000204475

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan April 15,2002 Indoor Air Quality Measurements Page 3 Stuyvesant High School (M477)______________ ATCProiectNo. 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 12:05 P.M,

Temperature

Indoor dry bulb temperature measurements ranged from 67.1°F to 74.7°F. Three (3) of the measurements were below the range of 68 to 75°F (at 50 percent relative humidity) recommended by ASHRAE Standard 55-1992 during the heating season (wintertime conditions). The outdoor temperature range was 54.8 to 55.7°F.

Relative Humidity

The relative humidity indoors ranged from 30.1 percent to 43.8 percent. All measurements were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort.. The outdoor relative humidity levels were 45.7 and 50.8 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 436 ppm to 1145 ppm. All of the CO2 measurements were within the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The outdoor (background) CO2 concentrations were 425 and 441 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1141 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.

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 ranged from Ippm to 2 ppm.

Respirable Particulates (PM2,5)

Respirable particulate concentrations* indoors ranged between 8 pg/m^ to 21 pg/m^ with an average of approximately 15 pg/m^. None of the measurements were above the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter or the USEPA recommendation of 40 pg/m^ for sensitive individuals and children. The outdoor respirable particulate concentrations v/ere 35 and 38 pg/m^.

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