NYC-WTC_000222500

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan April 24, 2002 Indoor Air Quality Assessment Page 3 P. S. 89M________________________________ ATC Project No. 15-19125-0297 K EA L-TI IE ENV iron M E NT A L M EA S IK EA1 F.NTS

ATC collected eighty (SO) sets of real-time environmental measurements consisting of seventy (70) from inside the school building and ten (10) from outdoors. All five lloors of the school building were surveyed. These results are described below.

Field data sheets are found in Attachment 1. Readings began at 8:00 A.M. and concluded at approximately 11:30 A.M.

Temperature

Indoor dry bulb temperature measurements ranged from 6-1 'F to 70.8 °F. All of the indoor measurements for temperature were below the range of 73 to 79°F (at 50 percent relative humidity) as recommended by the ASFIRAE Standard 55-1992 during the summer season . The outdoor temperature measurements ranged from 46.8 °F to 48.1 °F.

Relative Humidity

The relative humidity indoors ranged from 24.6 to 36.5 percent. Sixty (60) of the indoor measurements for relative humidity were below and ten (10) measurements were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity measurements ranged from 31.8 to 34.3 percent.

Carbon Dioxide Conceiitratioii

Carbon dioxide concentrations indoors ranged from 472 ppm to 1050 ppm. All of the indoor measurements for COg were below above the ASFIRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The maximum outdoor (background) COg concentration was 455 ppm. Therefore, the maximum acceptable level of COg at this location was 1155 ppm (background level + 700 ppm). 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 COg indoors is occupant respiration. The school building was occupied during ATC’s assessment.

Carbon Monoxide Coiiecntraiioii

Carbon monoxide concentrations indoors was 0 ppm for all readings. These concentrations were below the NPAAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentration was 0 ppm for all collected readings.

Respirable Particulates (PM2.5)

Respirable particulate concentrations* indoors ranged between 5 pg/m^ to 17 ug/m^. The average PMg 5 concentration for the entire school building was approximately 9 g/m^. All of the indoor and outdoor measurements were below the NPAAQS of 65 [ig/m^ 24-hour average concentration of particulate matter 2.5 miciometers or less in aerodynamic diameter and the USEPA recommended concentration of 40 pg/m^ for sensitive individuals and children. The outdoor respirable particulate concentration measurements ranged from 16 to 20 pg/m^ with an average of 18 pg/m^.

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