NYC-WTC_000187685

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan March 14, 2002 Indoor Air Quality Assessment Page 3 P. S. 150M ATC Proiect No. 15-19125-0289

Real-Time Environmental Measurements

ATC collected forb,' (40) sets of real-time environmental measurements consisting of thirty (30) from inside the school building and ten (10) from outdoors. All three floors of the school building were surveyed. These results are described below.

Field data sheets are found in Attachment 1. Readings began at 12:00 P.M. and concluded at approiKimately 1:30 P.M.

Ternperature

Indoor dr\' bulb temperature measurements ranged from 72.0.8°F to 76.2°F. Eighteen (18) of the measurements were above the range of 68 to 75°F (at 50 percent relative humidity) as recommended by the ASH RAE Standard 55-1992 during the heating season (wintertime conditions). The outdoor temperature measurements ranged from 46.0 to 47.3 "F.

Rc’laiive Humidity

The relative humidity indoors ranged from 32.4 to 54.8 percent. All of the measurements were Within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity measurements ranged from 53.0 to 61.3 percent.

Cjrhon Dioxide Concentration

Uarbon dioxide concentrations indoors ranged from 514 ppm to 953 ppm. All of the CX)? measurements were within the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The maximum outdoor (background) CO2 concentration was 445 ppm. Tlterefore, the maximum acceptable level of CO2 at this location was 1145 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 CO2 indoors is occupant respiration. The school building was occupied during ATC’s assessment.

Carhem Monoxide Ccn^mtration

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

Respirable Particulates (PM2 5)

Respirable particulate concentrations* indoors ranged between 23 pg/m^ to 38 pg/m^. None of the measurements were above the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. The average PM?.5 concentration for the entire school building was approximately 32 pg/m^. The PM?.5 average concentration was below the USEPA recommended concentration of 40 pg/m^ for sensitii’e individuals / children. The outdoor respirable particulate concentration measurements ranged fromi 58 to 61 pg/m^ with an average of 59 pg/m^.

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NYC-WTC_000187687