Indoor air quality report, PS 234M, Jan 2002

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan January 25, 2002 Indoor Air Quality Assessment Page 3 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-five (55) from inside the school building and five (5) 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 10:00 A.M. and concluded after 1:15 P.M.

Temperature

Indoor dry bulb temperature measurements ranged from 63.6 °F to 70.3 °F. Forty (40) measurements were below 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 51.4 to 58.0 °F.

Relative Humidity

The relative humidity indoors ranged from 37.4 percent to 76.3 percent. Three (3) measurements were above the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity ranged from 47.0 to 81.9 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 494 ppm to 790 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 490 to 585 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1285 ppm (background level -1- 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 29 pg'nY to 65 pg/m^. All measurements were equal or 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

CONFIDENTIAL, CITY_21MC100_003444686 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT. 2008

NYC-WTC_000177849