NYC-WTC_000187665

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan March 26, 2002 Indoor Air Quality Assessment Page 3 _ ATC Project No. 15-19125-0289

Real-Time E^mkoamem al Measurements

.ATC collected forty (40) sets of real-time environmental measurements consisting of thirty (30 ) jfom 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 m Attachment 1. Readings began at 2:00 P.M. and concluded at ajiproximately 3;30 P.M.

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indoor dry bulb temperature measurements ranged from 69.8'^F to 74.3°F. All of the measurements were within rhe range of 68 to 75°F (at 50 percent relative humidip') a.s recommended by the ASHRAE Standard 55-1992 during the heating season (wintertime condi tions). The outdoor temperature measurements ranged from 48.1°F to 49,5°F.

yy^Hy-Uiidiiy rhe relative humidity indoors ranged from 17.6 to 21.6 percent. All of the measurements were below the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor ri'lative humidity measurements ranged from 21.1 to 24.1 percent.

Carbon Dioxide Concenti^'on

Carbon dioxide concentrations indoors ranged from 505 ppm to 809 ppm. Al! of the CO2 measurements were within the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The maximum outdoor (background) C'O2 concentration was 420 ppm. Therefore, the maximum acceptable level of COp at this location was 1120 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 wa.s occupied during ATC’s assessment.

Carhan MonoxideCo^e^ation

Carbon monoxide indoor concentrations were 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) PP'ti.

Respirable particulate concentrations* indoors ranged between 8 pg/m^ to 16 pg/m-. None of the measurements were above the NPAAQS of 65 pg/m or above the USEPA recommendation of 40 pg/m^ for sensitive individuals and children. The average PM2 5 concentration for the entire school building was approximately 13 pg/m^. Ibe PM2.5 average concentration was below the USEPA recommended concentration of 40 pg/m^ for sensitive individuals and children. The outdoor respirable particulate concentration measurements ranged from 16 to 32 pg/m^ with an average of 24 pg/m^.

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NYC-WTC_000187667