NYC-WTC_000212725

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan June 5, 2002 indoor Air Quality Assessment Page 3 L S..^4M___ ___________ _ AIR J ’roicct No. J Y-J 9J 25-p279 A'l'C collected sixty (60) sets of real-time environmental measurements consisting of fifty (50) from inside the school buildi ig and ten (10) outdoors. All three lloors of the school were surveved. 1 hese results are described below.

Field data sheets are found in Attachment 1. Readings began at 7:00 AM and concluded after i2:?6 P.M.

Tcinperciture

Indoor dry bulb temperature measurements ranged from 7.T5 °F to 77.4 °F. /Ml of the indoor measurements for temperature were within the range of 73 to 79°F (at 50 percent relative humidity) .is recommended by .ASHRAE Standard 55-1992 during the summer season, fhe outdoor temperature measurements ranged from 68.1 °F to 68.4 °F.

The relative humidity indoors ranged from 41.7 percent to 47.1 percent. All of the indoor- measurements for relative humidity were within the ASHRAT-recommended range of 30 to 60 percent fo,” occupant comfort. The outdoor relative humidity ranged from 44.6 percent to 44.S percent.

Ciirhojp Dioxide CoHcetUradon

Carbon dioxide concentrations indoors ranged from 550 ppm to 1190 ppm. All of the indoor measurements were wnthin the ASIIRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The maximum outdoor (background) CO2 concentration was 626 ppm. Therefore, the maximum acceptable level of CO? at this location was 1326 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 i.s occupant respiration.

C'lirhon M’^fioxide Ctpwj^iitniJjoji

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 w'as also 1 ppm for all readings.

Rexpiruble Parijciilates (PM2,5?

Respirable particulate concentrations* indoors ranged between 7 pg/m^ to 19 pg/m-^ with an average approximately 13 pg/m^- None of the measurements collected indoors for .-espirable 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. Fhe outdoor respirable particulate concentration ranged from 30 pg/m-^ to 33 pg/m^ with an average of approximately 32 pg/m^.

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

CITY_21MC100_002852098

NYC-WTC_000212727