NYC-WTC_000210988

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan May 28, 2002 Indoor Air Quality Assessment Page 3 P. S. 89M_______________________________ ATC Project No. 15-19125-0297 Real-Time Environmental Measurements

?ArC collected seventy-nine (80) sets of real-time environmental measurements consisting of seventy (70) from inside the school building and ten (10) from outdoors. All five floors of the school building were surveyed. These results are described below.

Field data sheets are found in Attachment 1. Readings began at 8:00 A.M. and concluded at approximately 11:30 A.M.

Temperature

Indoor dry bulb temperature measurements ranged from 66.6°F to 71.7 °F. All of the indoor measurements for temperature were below the range of 73 to 79°F (at 50 percent relative humidity) as recommended by the ASHRAE Standard 55-1992 during the summer season . The outdoor temperature measurements ranged from 61 °F to 64.8°F.

Relative Humidity

Tlie relative humidity indoors ranged from 37 to 45.4 percent. All of the indoor measurements for relative humidity were within the ASHRAE-recommended range of 30 to 60 percent for occupant comfort. The outdoor relative humidity measurements ranged from 42.8 to 49.2 percent.

Carhan Dioxide Concentration

Carbon dioxide concentrations indoors ranged from 516 ppm to 1140 ppm. All of the indoor measurements for CO2 were below the ASHRAE Standard 62-1999 recommended maximum concentration of <700 ppm above the background level. The maximum outdoor (background) CO2 concentration was 528 ppm. Therefore, the maximum acceptable level of CO2 at this location was 1228 ppm (background level + 700 ppm). Carbon dioxide measurements are used a.s an indicator of available outside makeup air. The primary source of CO2 indoors is occupant respiration. The school building wa;5 occupied during ATC’s assessment.

Carbon Monoxide Concentration

Carb<m 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 collected readings.

Respirable Particulates (PM2,5)

Respirable particulate concentrations* indoors ranged between 18 pg/m^ to 41 pg/m^. The average PM2.5 concentration for the entire school building was approximately 28 pg/m^. All of the indoor measurements were below the NPAAQS of 65 pg/m^ 24-hour average concentration of particulate matter 2.5 micrometers or less in aerodynamic diameter. One (1) of the seventy (70) instantaneous readings was above the USEPA recommended concentration of 40 pg/m^ for sensitive individuals and children. The outdoor respirable particulate concentration measurements ranged from 70 to 94 pg/m^ with an average of 90 pg/m^.

CITY_21MC100_0 02863226

NYC-WTC_000210990