NYC-WTC_000205292

NYC 9/11 Public Portal Document

05/0-6/2.002 11:29 FAX 212 353 8306 ATC ®005

Mr. Bernard P. Orlan May 6,2002 Indoor Air Quality Assessment Page 4 P_. S. 89M________________ ATC Project No. 15-19125-0297 respirable particulate concentration measurements ranged from 42 to 46 with an average of 45 pg/m^.

* 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. Sixty-two (62) of the indoor measurements for temperature were below the range of 73 to 79°? (at 50 percent relative humidity) as recommended by the ASHRAE Standard 55-1992 during the summer season. 3. Thirty-eight (38) of die indoor measurements for relative humidity were below and thirty- two (32) were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. 4, Ten (10) of the indoor measurements for CO2 were above die ASHRAE Slandard 62-1999 recommended maximum concentration of <700 ppm above the background level. The highest reading (1416 ppm) was taken in room 404 at 9:54 AM with 31 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. The school building was occupied during ATC’s assessment. 5. Ail 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 and the USEPA recommended concentration of 40 pg/m^ for sensitive individuals and children.

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