IAQ Report Cover Letter, 90 Trinity Place, Apr 2002

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan April 30, 2002 Indoor Air Quality Assessment Page 3 H.S. for Leadership & Public Service (M894) ATC Project No. 15-19125-0290 Real-Time Environmental 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 were collected in the morning and evening. The results are described below.

Temperature

Indoor dry' bulb temperature measurements ranged from 71.2 °F to 76.9 °F. Forty'-three (43) of the indoor measurements for temperature were below and eighty-five (85) were within the range of 73 to 79°F (at 50 percent relative humidity) recommended by ASHRAE Standard 55-1992 during the summer season . The outdoor temperature ranged from 63.2 to 66.9 °F.

Relative Humidity

The relative humidity indoors ranged from 23.3 percent to 31.2 percent. One hundred and seven (107) of the indoor measurements for relative humidity were below and twenty-one (21) measurements were within the ASHRAE-recommended range of 30 to 60 percent for occupant cornfort. The outdc'or relative humidity range was 23.6 to 28.6 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 457 ppm to 1346 ppm. Three (3) of the indoor measurements for CO2 were above the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The outdoor (background) CO2 concentration was 596 ppm. Therefore, the maximum acceptable level of COg at this location was 1296 ppm (background level + 700 ppm). The highest measurement (1346 ppm) was collected in room 905 at 10;30 AM with 34 occupants. 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 ranged from 1 ppm to 2 ppm These concentrations were below the NI’AAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentrations was Ippm for all readings.

Respirable Particulates (PM2^j)

Respirable particulate concentrations* indoors ranged between 6 ug/m^ to 17 pg/m^ with an average 12 pg/m^ All of the indoor and outdoor measurements for PMg.s were below the NPAAQS of 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 such as asthmatic people and children. The outdoor respirable particulate concentrations ranged from 6 pg/m^ to 38 pg/m^ with an average of 27 pg/m^. * The measurements made during this assessment were instantaneous readings, the NPAAQS is a 24-hour average.

CONFIDENTIAL, CITY_21MC100_003464098 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT. 2008

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