NYC-WTC_000223930

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan May 13,2002 Indoor Air Quality Assessment Page 3 P. S. 234M______________ ATC Project No. 15-19125- 0279

Field data sheets are found in Attachment 1. Readings began at 2;00 P.M. and concluded after 4; 15 P.M.

Temperature

Indoor dry bulb temperature measurements ranged from 70.3 °F to 76.1 °F. Three (3) indoor measurements for temperature were below the range of 73 to 79°F (at 50 percent relative humidity) as recommended by ASHRAE Standard 55-1992 during the summer season. The outdoor temperature measurements ranged from 68.0 to 74.3 °F.

Relative Humidity

The relative humidity indoors ranged from 32.5 percent to 50.3 percent. All indoor measurements for relative humidity were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity ranged from 28.7 to 52.9 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 820 ppm to 1648 ppm. Three (3)of the measurements were above the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The maximum outdoor (background) CO2 concentration was 609 ppm. Therefore, the maximum acceptable level of COj at this location was 1309 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 outdoor air. The primary source of CO2 indoors is occupant respiration.

Carbon Monoxide Concentration

Carbon monoxide concentrations indoors ranged from 0 ppm to 1 ppm. These concentrations were below the NPAAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentrations were 1 ppm for all readings.

Respirable Particulates (PM2 s)

Respirable particulate concentrations* indoors ranged between 8 pg/m^ to 50 pg/m^ with an average approximately 16 pg/m’' All measurements collected indoors for respirable particulate concentrations were below the NPAAQS 65 pg/m’ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. One (1) indoor measurement was above the USEPA recommended concentration of 40 pg/m’ for sensitive individuals and children. The outdoor respirable particulate concentration ranged from 12 pg/m’ to 98 pg/m’ with an average of approximately 23 pg/m\

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

TVOC Concentration

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