NYC-WTC_000222495

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan April 22, 2002 Indoor Air Quality Assessment Page 4 p. S. 89M_________________________________ _ ________ ATC Project No. 15-19125-0297 seventy (70) instantaneous indoor measurements were above USEPA recommended concentration of 40 pg/m^ for sensitive individuals and children. The outdoor respirable particulate concentration measurements ranged from 58 to 122 pg/m^ with an average of 89 pg/m3. Nine (9) of the outdoor measurements were above the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. All of the outdoor instantaneous readings 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 Concentrations TVOCs were not detected anywhere inside the building (0.0 ppm). The outdoor TVOC concentration was also 0.0 ppm.

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

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

1. Concentrations of CO and TVOCs were below applicable standards and guidelines. 2. Sixteen (16) of the indoor measurements for temperature were below and fifty-four (54) were within the range of 73 to 79°F (at 50 percent relative humidity) as recommended by the ASHRAE Standard 55-1992 during the summer season . 3. All of the indoor measurements for relative humidity were within the ASHRAE- recommended range of 30 to 60 percent for occupant comfort. 4. Four (4) 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 concentration was detected in room # 402 (1432 ppm) at 10:00 AM with 32 occupants. Levels above the recommended maximum do not indicate a health risk. Carbon dioxide measurements are used as an indicator of available outside makeup air. The primary source of CO2 indoors is occupant respiration. 5. All of the indoor measurements were below the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. Thirty- two (32) of the seventy (70) instantaneous indoor measurements were above USEPA recommended concentration of 40 pg/m^ for sensitive individuals and children. Nine (9) of the outdoor measurements were above the NPAAQS of 65 pg/m- 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. All of the outdoor instantaneous readings were above the USEPA recommended concentration of 40 pg/m^ for sensitive individuals and children.

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