NYC-WTC_000196071

NYC 9/11 Public Portal Document

AKRFJnc. 111-115 Broadway, New York, New York

humidity levels observed throughout the buildings were within the recommended levels. Temperature readings up to 79.4 degrees Fahrenheit were observed within the building. However, because temperature and the remaining environmental conditions are heavily dependent upon occupancy and the building systems’ meeting of those occupancy loads, AKRF does not anticipate that this is an immediate area of concern. Carbon Dioxide fCO?) Carbon dioxide is a normal constituent in the air. Exhaled breath from building occupants is the primary source of carbon dioxide indoors. Carbon dioxide has been widely used in the industrial hygiene community as a surrogate for various occupant­ generated indoor contaminants, such as cigarette smoke and bioeffluents, that are known to cause annoyance, irritation, or discomfort among building occupants. For buildings or zones of buildings where air cleaning to remove smoke and bioeffluents is not provided, the performance criteria established in ASHRAE standard 62-1999 (Ventilation for Acceptable Indoor Air Quality), recommends that carbon dioxide concentrations be maintained below 700 ppm above the outside air level (equivalent to about 15 cubic feet per minute [cfrn] outdoor air per occupant). Carbon dioxide levels throughout the buildings were observed to be less than 1,000 ppm (estimated from 700 ppm in addition to an outdoor level of 300 ppm). Carbon Monoxide ICO) Carbon monoxide is a by-product of combustion. ASHRAE Standard 62-1999 recommends that indoor airborne carbon monoxide concentrations do not exceed 9 ppm. The intent of the recommendation is to prevent annoyance and discomfort among a substantial number of occupants. AKRF compared indoor and outdoor carbon monoxide concentration levels for evaluation purposes. Indoor concentrations exceeding outdoor concentrations would suggest an indoor source of carbon monoxide, such as an improperly vented combustion appliance, which should be corrected. The OSHA PEL is 50 ppm, while the NIOSH REL is 35 ppm and the ACGIH TLV is 25 ppm. Carbon monoxide levels observed throughout the buildings were less than 2 ppm.

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NYC-WTC_000196079