NYC-WTC_000209856

NYC 9/11 Public Portal Document

Tribeca Park -400 Chambers Street ATC Project No.: 09622-0012 Related Management Company, L.P. February 15, 2002 Page 5

Based upon analytical sample results for all samples recording levels below the AHERA clearance requirement, it is ATC’s opinion that the ambient air samples collected throughout the building are representative of the ambient conditions at the time of testing and that the areas tested meet an acceptable criterion for re-occupancy.

Fiberglass in Air via PCM Twelve ambient air samples collected within the common areas lobby were analyzed for fiberglass using the Phase Contrast Microscopy (PCM) analytical method. All samples collected recorded fiber levels less than 0.01 f/cc In the absence of a specific ambient air standard for fiberglass, ATC has selected as a criteria for acceptable ambient air sample sets, the NYCDEP re-occupancy requirement following an asbestos abatement action of an average of less 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

PCB’s in Air One ambient air sample collected within the lobby and analyzed for PCB’s recorded analytical results less than analytical detection limit.

Indoor Air Quality The lAQ evaluation included collection of seventy-five real-time measurements of temperature, relative humidity, carbon dioxide (CO2), carbon monoxide (CO), respirable particulates and total volatile organic compounds (TVOC). Currently, there are no regulatory standards for indoor air quality in non-industrial buildings, such as residential units. For the real-time data collected, ATC uses the commonly accepted guidelines cited in the following publications. • Ventilation for Acceptable Indoor Air Quality (ASHRAE 62-1999), American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE); • Thermal Environmental Conditions for Human Occupancy (ASHRAE 55-1992); • Industrial Hygienists Guide to Indoor Air Quality Investigations (1993), American Industrial Hygiene Association (AlHA).

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NYC-WTC_000209861