NYC-WTC_000199569

NYC 9/11 Public Portal Document

NYC DEP BflNHazmat Exec Fax:7185953744 Dec .13 '01 11:07 P. 02

Ambient'Air Sampling QSBOeiflVBQ IWC.

IwelvQ ambient eir samples collected within the common areas lobby were analyzed for fibarglaas using the Phase Contrast Microscopy (PCM) analytical method. All samples collected recorded fiber levels less than 0.01 f/cc in the absence of e specific ambient air standard for fiberglass, ATC has selected as a criteria for acceptable ambient air sample sets, the NYCDEP re-occupancy nsquirement following an asbestos abatement action of an average of lees than 0.01 fibers per cubic centimeter (o.ol f/cc’). In conclusion, based upon the analytical results for fiberglass recording fiber concentrations below the NYC acceptable airborne clearance requirement following an abatement action, It Is ATC’s opinion that the ambient air samples collected throughout the building meet an acceptable criterion for re-occupancy

8n Ono ambient air sample collected within the lobby and analyzed for PCB's recorded analytical results less than analytical detection limit.

tedQQf A!/ ^uall^V The IAQ evaluation included collection of seventy-five real-time measurements of temperature, relative humidity, carbon dioxide (COj), carbon monoxide (CO), respirable particulates and total volatile organic compounds (TVOC). Currently, thara are no regulatory standards for indoor air quality in non-indusWal buildings, such as residential units. For the real-time data collected, ATC uses the commonly accepted guidelines cited in tha following publications; o Ventilation for Acceptable Indoor Air Quality (ASHRAE 62'1999). American Society of Heating, Refrigerating, and Air-Conditioning Enginaers (ASHRAE); 0 Thermal Environmental Conditions for Human Occupancy (A SHRAE 55-1992); 0 Industrial Hygienists Guide fo Indoor Air Quality Investigations (1993), American Industrial Hygiene Association (AIKA).

TARGET LgVEL AGEMCV OR ORGANSZATtON Carbon Dioxide <700 parts par million (ppm) ASHRAE 82 (CO,) above background level Carbon Monoxide 0 ppm USEPA NPAAQS (as Cited in (CO) ASHRAE 62) Respirable Partidas SO micrograms per cubic USEPA NPAAQS (as cited in (PMw)___________ mater of air (pg/m’) ASHRAE 62) ___________ Tomperatura Summer. 73-79T at 60% RH ASHRAE 55 Winter: 8B-75T at 60% RH Relative Humidity 30-60% ASHRAE 55

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NYC-WTC_000199570