NYC-WTC_000226869

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan January 17, 2002 Indoor Air Quality Assessment Page 3 P. S. 89 (Manhattan) ATC Project No. 15-19125-0297

Real-Time Environmental Measurements

ATC collected thirty (30) sets of real-time environmental measurements consisting of twenty- three (23) from the pt floor of the school building and seven (7) outdoors from the playground as per the request of the Parents associations environmental consultant. These results are described below. The field data sheets are found in Attachment 1.

Temperature

Indoor dry bulb temperature measurements ranged from 65.2 °F to 69.7 °F. Nineteen (19) measurements were below the range of 68 to 75°F (at 50 percent relative humidity) recommended by ASHRAF Standard 55-1992 during the heating season (wintertime conditions). These measurements were collected from the 1st floor. The outdoor temperature measurements at the playground ranged from 44.0 to 45.2 °F.

Relative Humidity

The relative humidity indoors ranged from 19.0 percent to 28.1 percent. All measurements were below the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity ranged from 20.0 to 21.0 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 409 ppm to 499 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 420, 435, 430, 435, 435, 440 and 430 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1140 ppm (background level 4- 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_s)

Respirable particulate concentrations* indoors ranged between 4 pg/m^ to 11 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 outdoor respirable particulate concentration ranged from 10-13 pg/m^.

* The measurements made during this assessment were instantaneous readings, the NPAAQS is a 24-hour average.

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