NYC-WTC_000219855

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan May 3, 2002 Indoor Air Quality Assessment Page 4 H.S. of Economics and Finance (M833) ATC Project No. 15-19125-0291 instantaneous measurements were above the USEPA recommended concentration of 40 pg/'m^ for sensitive individuals and children.

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

TVOC^ncentration

TVOCs were not detected anywhere inside the building (0.0 ppm). The outdoor TVOC concentration was also 0.0 ppm.

OBSERVATIONS

Diuing this assessment, ATC noted the following: • The interior of the building appeared clean and free of dust and debris; • The building was occupied at the time of the assessment; • No smoke odor was detected in the building;

FINDINGS

Based on the real-time measurements, the following findings are presented;

1. Indoor concentrations of CO and TVOCs were below applicable standards and guidelines. 2. Nineteen (19) temperature measurements were below and sixty-nme (69) measurements were within the range of 73 to 79°F (at 50 percent relative humidity) recommended by ASHRAE Standard 55-1992 during the summer season. 3. Three (3) of the indoor measurements for relative humidity were above and eighty-five (85) measurements were within the ASHRAE recommended range of 30 to 60 percent for occupant comfort. 4. Eleven (11) of the indoor measurements for CO2 were above the ASHRAE Standard 62- 1999 recommended maximum concentration of <700 ppm above the background level. The highest reading (2040 ppm) was measured in Staircase A around 11:25 A.M. 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. 5. One (1) of the indoor measurements for respirable particulates was above the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. Five (5) of the eighty-eight (88) indoor instantaneous measurements were above the USEPA recommended concentration of 40 pg/m3 for sensitive individuals and children. Six (6) of the outdoor measurements for respirable particulates were above the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. Eleven (11) the twelve (12) outdoor instantaneous measurements were above the USEPA recommended concentration of 40 pg/m^ for sensitive individuals and children.

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NYC-WTC_000219858