NYC-WTC_000197534

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan October 24,2001 Indoor Air Quality Assessment Page 3 Stuwesant Hish School (M477) ATC Project No. 15-19125-0246

Real-Time Environmental Measurements

ATC collected one hundred and twenty-eight (128) sets of real-time environmental measurements consisting of one hundred and twenty-six (126) in the school building and two (2) outdoors. All ten floors of the school were surveyed. These results are described below. Field data sheets are found in Attachment 1. Readings began at 8:45 A.M. and concluded at 2:45 P.M.

Temperature

Indoor dry bulb temperature measurements ranged from 69.6 °F to 76.4 °F. Only three (3) measurements were slightly above the range of 69 to 76°F (at 50 percent relative humidity) recommended by ASHRAE Standard 55-1992 during the heating season (wintertime conditions). These measurements were in rooms on the 2nd floor, the highest was only 0.4°F above the range. The outdoor temperature range was 63.1 to 65.9 °F. ■

Relative Humidity

The relative humidity indoors ranged from 50.6 percent to 74.5 percent. Fifty-four measurements were above the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity range was 71.6 to 79.0 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 408 ppm to 2755 ppm. Thirty (30) CO2 measurements were above the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The outdoor (background) CO2 concentration was 345 ppm. Therefore, the acceptable level of COg at this location was 1045 ppm (background level -I- 700 ppm). Rooms with CO2 levels above the recommended maximum were found on all floors. 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 COg indoors is occupant respiration.

Carbon Monoxide Concentration

Carbon monoxide concentrations indoors were 0 ppm for all readings except for one reading in the IQth floor hallway which was 1 ppm. 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 52 pg/m^ and 132 ug/m^. One hundred and seven (107) measurements were above the NP.AAQS of 65ug'm^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. Rooms with particulate concentrations above the NP.YAQS were found on all floors. The outdoor respirable particulate concentration range was 108 to 136 pg/m^.

CITY_21MC100_003045656

NYC-WTC_000197536