NYC-WTC_000214366

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan April 19, 2002 Indoor Air Quality Assessment Page 3 P. S. ISOM ATC Project No. 15-19125-0289

Real-Time Environmental Measurements

ATC collected forty (40) sets of real-time environmental measurements consisting of thirty (30) from inside the school building and ten (10) from outdoors. All three floors of the school building were surveyed. These results are described below.

Field data sheets are found in Attachment 1. Readings began at 12.00 P.M. and concluded at approximately 1:30 P.M.

Temperature

Indoor dry bulb temperature measurements ranged from 72.6 °F to 74.7 °F. Four (4) of the indoor measurements for temperature were below and twenty-six (26) measurements were within the range of 73 to 79 °F (at 50 percent relative humidity) as recommended by the ASHRAF Standard 55-1992 during the summer conditions. The outdoor temperature measurements ranged from 83°F to 84.4°F. Relative Humidity

The relative humidity indoors ranged from 45 to 50 percent. All of the measurements were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity measurements ranged from 47 to 48.8 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 709 ppm to 890 ppm. All of the CC? measurements were below the ASHRAF Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The maximum outdoor (background) CO2 concentration was 495 ppm. Therefore, the maximum acceptable level of CO? at this location was 1195 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 outside makeup air. The primary source of CO2 indoors is occupant respiration. The school building was occupied during ATC’s assessment.

Carbon Monoxide Concentration

Carbon monoxide indoor concentrations was 3 ppm for all readings. These concentrations were below the NPAAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentration was 3 ppm for all collected readings.

Respirable Particulates (PM2,5) ppm.

Respirable particulate concentrations* indoors ranged between 16 pg/m^ to 36 pg^m^. All of the indoor and outdoor measurements for PM2.5 were below the NPAAQS of 65 pg/m^ for 24- hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter and the USEPA recommendation of 40 pg/m^ for sensitive individuals and children. The average PM2.5 concentration for the entire school building was approximately 26 pg/m^.

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NYC-WTC_000214368