NYC-WTC_000199261

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan August 28, 2002 Indoor Air Quality Assessment Page 3 J.H.S. 131 M____________________________ ATC Project No. 15-19125-0346 REAL-TIME^NVIRONMENTAL MEASUREMENTS

ATC collected fifty (50) sets of real-time environmental measurements consisting of forty-seven (47) in the school building and three (3) outdoors. All floors of the school were surveyed. Field data sheets are found in the Attachment. Readings were collected in the morning and evening. The results are describ id below.

Temperature

Indoor dry bulb temperature measurements ranged from 76.9 to 89.3 °F. Forty (40) of the indoor measurements were above the range of 73 to79 °F (at 50 percent relative humidity) recommended by ASHRAE Standard 55-1992 during the summer season. The outdoor temperature ranged from 81.8 to 83.5 °F.

Relative Humidity

The relative humidity indoors ranged from 41.2 percent to 59.2 percent. All of the indoor measurements for relaiive humidity were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity measurements ranged from 50.2 to 50.5 percent.

Carbon Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 419 ppm to 1193 ppm. Two (2) of the indoor measurements for CO2 were above the ASHRAE Standard 62-1999 recommended maximum concentratic n of <700 ppm above the background level. The outdoor (background) CO2 concentration was 411 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1111 pprr (background level + 700 ppm). The highest reading was measured in the basement office with ) occupants at 2:46 PM. 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 1 ppm to 2 ppm. These concentrations were within the NPAAQS/ASHRAE guideline of 9 ppm. The outdoor CO concentrations was 2 ppm for all readings

Respirable Particulates (PM2,5)

Respirable particulate concentrations* indoors ranged between 14 pg/m^ to 78 pg/m^ with an average 33 pg/m^- Two (2) of the indoor measurements for PM2 5 were above the NPAAQS of 65 pg/m3 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. Eight (8) of the forty-seven (47) instantaneous indoor readings were above the USEPA recommended concentration of 40 pg/m^ for sensitive individuals such as asthmatic people and children. The outdoor respirable particulate concentrations ranged from 38 pg/m3 to 39 pg/m^ with an average of 38 pg mA All of the outdoor measurements for PM2.5 were below the NPA/.QS 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/m3 for sensitive individuals such as asthmatic people and children.

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NYC-WTC_000199263