NYC-WTC_000226873

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan January 18, 2002 Indoor Air Quality Assessment Page 3 P. S. 89 (Manhattan) ATC Project No. 15-19125-0297

Real-Time Environmental Measurements

ATC collected fifty (50) sets of real-time environmental measurements consisting of fourty-eight (48) from inside the school building and two (2) outdoors from the playground. All five 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 9:50 P.M.

Temperature

Indoor dry bulb temperature measurements ranged from 67.1 °F to 78.0 °F. Four (4) measurements were below and three (3) were above 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 measurements at the playground ranged from 45.5 to 45.9 °F.

Re/ative Humidity

The relative humidity indoors ranged from 19.0 percent to 33.0 percent. Only one (I) measurement was within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. All other relative humidity measurements were below the ASHRAE-recommended range. The outdoor relative humidity ranged from 25.4 to 28.0 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 445 ppm to 629 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 were 430 and 438 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1138 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 during ATC’s assessment was not occupied.

Carbon Monoxide Concentration

Carbon monoxide concentrations indoors were 0 ppm for all readings. These concentrations were below the NPAAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentration was 0 ppm.

Respirable Particulates (PM2,5)

Respirable particulate concentrations* indoors ranged between 19 p-g/m^ to 44 pg/m^. All 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

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