IAQ Report Cover Letter, 90 Trinity Place, Mar 2002

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan March 27, 2002 Indoor Air Quality Assessment Pages H.S. for Leadership & Public Service fM894) ATC Project No. 15-19125-0290 Real-Time Eymroxmental Measurements

ATC collected one hundred and forty (140) sets of real-time environmental measurements consisting of one hundred and twenty-eight (128) in the school building and twelve (12) outdoors. All fourteen floors of the school were surveyed. Field data sheets are found in the Attachment. Readings began at 10:11 A.M. and concluded after 6:23 P.M. The results are described below.

Temperature

Indoor dry' bulb temperature measurements ranged from 71.5 °F to 78.8 °F. One hundred and one (101) indoor measurements for temperature were above and twenty-seven (27) measurement were within 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 rar ge was 39.6 °F to 46.2 °F.

Relative Humidity’

The relative humidity indoors ranged from 26.2 percent to 39.9 percent. One hundred and twenty-one (121) of the indoor measurements for relative humidity were below and seven (7) measurements were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity range was 22.4 to 34.0 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 487 ppm to 1398 ppm. One (1) of the indoor measurements for CO2 was above the ASHRAE Standard 62-1999 recommended maximum concentration of a700 ppm above the background level. The outdoor (background) CO2 concentration was 439 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1139 ppm (background level + 700 ppm). The highest measurement was taken in the gymnasium at 12:54 PM with one (1) occupant. 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.

Carbon Monoxide Concentration

Carbon monoxide c:oncentrations indoors ranged from 1 ppm to 2 ppm. These concentrations were below the NPAAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentrations ranged from 2 ppm- 6 ppm

Respirable Particulates (PM2,5)

Respirable particulate concentrations* indoors ranged between 3 pg/m^ to 20 pg/m^ with an average 6 pg/m-^- All of the indoor measurements for PM2.5 were below the NPAAQS of 65 pg/m3 24-houT 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 such as asthmatic people and children. The outdoor respirable particulate concentrations ranged from 20 pg/m^ to 68 pg/m^ with an average of 32 pg/m^. One (1) of the outdoor measurements for PM2.5 was above the NPAAQS of 65 pg/m^ 24-hour average

CONFIDENTIAL, CITY_21MC100_007741198 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT. 2008

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