NYC-WTC_000212711

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan May 30. 2002 Indoor Air Quality Assessment Page 3 P S. 234M ATC Project No. 15-19125-0279

Real-Time Environmentai. Measurements

A'fC collected sixty (60) sets of real-time environmental measurements consisting of fifty-onc (5 I ) from inside the school building and nine (9) outdoors. All three floors of the school were surveyed. These results are described below.

Field data sheets are found in Attachment 1. Readings began at 7:00 .AM and concluded after 12:50 P.M.

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Indoor dry bulb temperature measurements ranged from 66.1 °F to 76.2 °F. Seventeen (17) indoor measurements for temperature were below and none of the measurements were above the range of 73 to 79°F (at 50 percent relative humidity) as recommended by ASFIRAE Standard 55- 1992 during the summer season. The outdoor temperature measurements was 66.1 °F for all readings.

Relative Humidity

The relative humidity indoors, ranged from 49 percent to 65.1 percent. Five (5) 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 was 65.1 percent for all readings.

Carhon Diavide Concentration

Carbon dio.xide concentrations indoors ranged from 512 ppm to 1261 ppm. One (1) of the measurements was above the ASURAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The maximum outdoor (background) ('(On concentration was 520 pprn. Therefore, the maximum acceptable level of CO2 at this location was 1220 ppm (background level + 700 ppm). The highest reading was recorded in room 206 at 11:47 AM with 20 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 was 1 ppm for al! readings. These concentrations were below the bPAAQS/ASHRAF guideline of 9 ppm. The outdoor CO concentrations was 1 ppm for all readings.

Re.'ipirable Particulales tPM2,5)

Respirable particulate concentrations* indoors ranged between 8 pg/m^ to 40 pg/m^ with an average approximately 13 pg/m^- None of the measurements collected indoors for respirable particulate concentrations were above the NPAAQS 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter and the USEPA recommerded concentration of 40 pg/m^ for sensitive individuals and children. The outdoor

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