Indoor air quality report, PS 234M, Jan 2002

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan January 29, 2002 Indoor Air Quality Assessment Pages P. S. 234M ATC Project No. 15-19125-0279

Real-Time Environmental Measurements

ATC collected sixty (60) sets of real-time environmental measurements consisting of fifty (50) from inside the school building and ten (10) 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 ll;00 P.M. and concluded after 2:20 P.M.

Temperature

Indoor dry bulb temperature measurements ranged from 63.6 °F to 73.3 °F. Thirty-six (36) measurements were below the range of 68 to 75°F (at 50 percent relative humidity) as recommended by ASHRAE Standard 55-1992 during the heating season (wintertime conditions). The outdoor temperature measurements ranged from 67.9 to 70.2 °F.

Relative Humidity

The relative humidity indoors ranged from 24.9 percent to 39.7 percent. Twelve (12) measurements were below the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity ranged from 24.4 to 30.9 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 502 ppm to 654 ppm. All CO2 measurements were below the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The outdoor (background) CO2 concentrations ranged 476 to 530 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1230 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. The school building was not occupied during ATC’s assessment.

Carbon Monoxide Concentration

Carbon monoxide concentrations indoors ranged from 1 to 0 ppm for all readings. These concentrations were below the NPAAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentrations also ranged from 0 to 1 ppm.

Respirable Particulates (PM2,$)

Respirable particulate concentrations* indoors ranged between 33pg/m3 to 70 pg/m^. All but three (3) measurements were below the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. The average PM2.5 concentration for the entire school building was approximately 48 pg/m^. This average concentration was below the USEPA recommended concentration for sensitive individuals such

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