NYC-WTC_000223184

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan June 26, 2002 Indoor Air Quality Measurements Page 3 Stuyvesant High School (M477)__________ ATC Project No. 15-19125-0246 Real-Time Environmentai. Mfasiirf.mf

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 12:45 P.M.

Temperature

Indoor dry bulb temperature measurements ranged from 70.0 °F to 78.8 °F. Fifty-nine (59) 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 80.2 to 82.5 °F.

Relative Humidity

The relative humidity indoors ranged from 52.2 percent to 65.8 percent. One (1) of the indoor measurements for relative humidity was above the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity levels were 56.2 and 63.4 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 521 ppm to 978 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) CO; concentrations were 394 ppm and 410 ppm. Therefore, the maximum acceptable level of CO, at this location was 1110 ppm (background level -t- 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 COj indoors is occupant respiration.

Carbon Monoxide Concentration

Carbon monoxide concentrations indoors ranged from 0 ppm to 1 ppm. These concentrations were within 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 27 pg/m’ to 37 pg/m’ with an average of approximately 32 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 or above the USEPA recommendation of 40 g/m’ for sensitive individuals and children. The outdoor respirable particulate concentrations were 62 and 71 pg/m’.

In addition to higher efficiency rating filters on their HVAC units, portable High Efficiency Particulate Air (HEPA) purifiers were placed in Rooms 327, 333, 638 and 740. The PM, j concentration range for these rooms was 30 - 35 pg/m’ with an average of approximately 32 pg/m’.

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