NYC-WTC_000209128

NYC 9/11 Public Portal Document

02^/2002_llil3, FAX 212 353 8306 ATC 0004/014

Mr, Bernard P, Orlan February 15, 2002 Indoor Air Quality Assessment Pages F, S- 89M ATC ProKCt No-15-19125-0297

real-Time enviro]nmental Measurements

ATC collected eighty (80) sets of real-time environmental measurements consisting of eight (S) I outdoors and thirty-two (32) inside in the morning (A-M.) and the same number of readings in the afternoon (P.M.). AU five floors of the school were surveyed. Tlie field data sheets are found in the Attachment. Readings began at 8:00 A.M. and concluded after 3:30 P.M. The results are described below:

Temperature

Indoor dry bulb temperature measurements ranged from 67.3®F to 75.1’? (A.M.) and 68.3°F to TS.S’F (PM). In the morning, five (5) of the measurements were below and one (1) measurement was above the range of 68 to (at 50 percent relative humidity) recommended by ASHRAE Standard 55-1992 during the heating season (wintertime conditions). In the afternoon, one (1) measurements was above the recommended range. The average outdoor temperature was 37.2"F (A.M.) and 45.4®F (P.M-).

Relative Humidily

The relative humidity indoors ranged from 7.4 to 14.3 percent (A.M.) and 11,0 to 19.8 percent (P.M,), All measurements were below the ASHRAE-rcconuncndcd range of 30 to 60 percent for occupant comfort. The outdoor relative humidity averaged 11.9 percent (A.M.) and 13.0 percent (P.M.).

Carbon Dioxi^Cpncentratipn

Carbon dioxide concentrations indoors ranged from 513 to 1090 ppm (A.M ) and 489 to 899 ppm (P.M.). All CO? measurements collected were below the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The outdoor (background) CO2 concentrations averaged 501 ppm (A.M.) and 478 ppm (P,M.). Therefore, the maximum acceptable level of CO2 at this location was 1201 ppm (background level ■+ 700 ppm). The highest indoor level was measured in Classroom 402. 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. The 2"^^ and 3rd floors of the school building were not occupied during ATC’s assessment.

Carbon Monoxide Concentration

Carbon monoxide was not detected indoors (0 ppm). The outdoor CO concentration was 1 ppm (A.M.) and 1 ppm (P.M.).

Respirable rartlculates

Respirable particulate concentrations* indoors ranged from 10 pg/m^ to 26 pg/m^ (A.M.) and 7 gg/mS to 15 pg/m^ (P.M.). All indoor measurements were below the NPAAQS of 65 pg/m^ (24-hour average). The average PM2_5 concentration* for the entire school building was approximately 18 pg/m^ (A.M.) and 10 pg/m^ (P.M.). None of the indoor measurements were above the USEPA recommended concentration of 40 p.g/m3 for sensitive individuals such, as

CnY_21MC10Ci_012151919 NYC-WTC_000209130