Indoor air quality measurements, P.S. 124M, Sept 2002

NYC 9/11 Public Portal Document

Mr Bernard P. Orlan September 11, 2002 Indoor Air Quality Assessment Page 3 PS. 124 M ATC Protect No. 15-19125-0350

Real-Time Environmental Measurements

ATC collected fifty (50) sets of real-time environmental measurements consisting of forty-eight (48) in the school building and two (2) outdoors All floors of the school were surveyed Field data sheets are found in the Attachment Readings were collected during school hours The results are described below

Temperature

Indoor dry bulb temperature measurements ranged from 75 6 to 83.1 °F Eighteen (18) of the indoor temperature measurements were above the range of 73 to 79 °F (at 50 percent relative humidity) recommended by ASHRAE Standard 55-1992 dunng the summer season The outdoor temperature measurements were 76 4 and 79 7 °F.

Relative Humidity

The relative humidity indoors ranged from 30 6 percent to 50 3 percent. All of the indoor measurements for relative humidity were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort The outdoor relative humidity measurements were 40 3 and 46 9 percent The high ambient relative humidity likely contributed to the elevated particulate levels reported below

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 760 ppm to 1302 ppm All indoor measurement for CO2 were below the ASHRAE Standard 62-2001 recommended maximum concentration of <700 ppm above the background level. The average outdoor (background) CO2 concentration was 670 ppm Therefore, the maximum acceptable level of CO2 at this location was 1370 ppm (background level + 700 ppm). Carbon dioxide measurements are used as an indicator of available outdoor air The primary source of CO2 indoors is occupant respiration

Carbon Monoxide Concentration

Carbon monoxide concentrations indoors ranged from 1 ppm to 2 ppm These concentrations were below the NPAAQS/ASHRAE guideline of 9 ppm The outdoor CO concentrations were 2 ppm for both readings

Respirable Particulates (PM2 5)

Respirable particulate concentrations* indoors ranged between 10 pg/m^ to 64 pg/m^. Fourteen (14) of the indoor measurements collected for PM2 5 were above the USEPA recommended concentration of 40 pg/m^ for sensitive individuals such as asthmatic people and children. The two outdoor respirable particulate concentrations were 32 pg/m^ and 52 pg/m^ with an average of 42 pg/m3

CONFIDENTIAL, CITY_2IMCl00_003431398 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT, 2008

NYC-WTC_000175531