NYC-WTC_000208064

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan December 19, 2001 Real-Time Air Monitoring Page 4 P.S. 89 (Manhattan) ATC Project No. 15-19125-0297

TABLE 4 REAL-TIME MEASUREMENTS 3:00 PM Lot no. Re•1. CO2 TVOC SO2 IHS NO NO2 tiid. (ppm) (ppml (ppn.) (ppm) 30 illilllls BOIst Playground 43.6 27J To" 2 ~2i (To 0.0 0.0 0.2 Hallway by 66.4 Ts TT T” “To o3o w 0.0 cafeteria Room 202 66.0 24.9 369 1 22 0.0 0.0 0.0 0.0 0.1 Roof by intake 4Z2 2^ 3^ ■3 13 To To" 7 ’ i> 7T7 7TT r-

All of the indoor measurements were collected when the building was unoccupied except for ATC and custodial personnel and do not indicate directly what conditions may be when students, faculty and staff are present. The temperature and relative humidity levels were below guideline ranges (Table 1), other parameters were acceptable. There were no appreciable changes any of the values over the measurement period. Temperature and CO2 levels would be expected to rise when the building is fully occupied.

The concentrations of NO2 were measured at 0.1 - 0.3 ppm for the instantaneous readings. There were no significant differences between indoor and outdoor levels. The NPAAQS for NO2 is an annual average concentration of 0.053 ppm. No secondary, i.e. short duration, ambient air quality standard exists.

24-HOUR PM2_s measurements

ATC placed three Dust Trak® aerosol monitors at different locations to record PM2.5 levels for 24 hour periods. The instruments logged dust levels every 60 seconds. Table 5 shows the locations, minimum, maximum and average concentrations. One instrument, located in the playground, stopped recording after 6 hours.

TABLE 5 24-HOUR PM2.5 CONCENTRATIONS (mg/m^) LOCA^ Dfiunox AVERAGE

Outdoors - Playground 5 hrs 57 min. 0.008 0.040 0.015 Hallway by cafeteria 24 hours 0.010 0.034 0.020

Roof by air intake 24 hours 0.007 0.031 0.015

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NYC-WTC_000208067