NYC-WTC_000212721

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan June 4,2002 Indoor Air Quality Assessment Page 3 P. S. 234M ATC Project No. 15-19125-0279 AFC/ collected sixty (60) sets of real-time environmental measurements consisting of fifty-one (51) from inside the school building and nine (9) outdoors. All three Boors of the school were surveyed. 1 hese results are described below.

Field data sheets are found in Attachment 1. Readings began at 7:00 AM and concluded after 12:36 P.M.

Temperattife

Indoor dr/ bulb temperature measurements ranged from 72.3 °F to 76.3 °F. Fifteen (15) of the indoor measurements for temperature were below the range of 73 to 79°F (at 50 percent relative humidity) as recommended by ASHRAE Standard 55-1992 during the summer season. The outdoor temperature measurements ranged from 68.2 °F to 68.4 °F.

Uplaiiye^hjjn^i^

The relative humidity indoors ranged from 24.1 percent to 36.3 percent. Thirty (30) of the indoor measurements for relative humidity were below the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity ranged from 33.6 percent to 33.8 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 546 ppm to 1361 ppm. One (1) of the indoor measurements was above the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The maximum outdoor (background) CO2 concentration was 610 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1310 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.

Catj}on^onoxj^ Concentration

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

Rexpirahle Particulates (PM2 ^yJ

Respirable particulate concentrations* indoors ranged between 5 pg/m^ to 12 pg/m-’ with an average approximately 9 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 recommended concentration of 40 pg/m^ for sensitive individuals and children. The outdoor respirable particulate concentration ranged from 14 pg/m^ to 16 pg/m^ with an average of approximately 16 pg/m^.

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

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NYC-WTC_0002 12723