Ambient air sampling report for 105 Duane Street, Feb 2002

NYC 9/11 Public Portal Document

Tribeca Tower— 105 Duane Street ATC Project No.: 09622-0014 Related Management Company, L.P. I February 11, 2002 Page 7

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.

Dioxins One sample twenty-four hour sample was collected using a spiked 75 mm polyurethane foam (PUF) sorbent plug and General Metal Works High Volume PS1 Sampler for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) [known collectively as dioxins] using a modified version of USEPA Method 23 (see attached analytical reports). All dioxin analyses were performed by Pace Analytical Services (see attached reports. The EPA's current screening level for dioxin in air, has been set to protect against significantly increased risks of cancer and other adverse health effects. This screening level is based on an assumption of continuous exposure for a year, to an average concentration of 0.16 nanograms per cubic meter (ng/m3) or 160 picograms per cubic meter (0.16 ng/m3 = 160 pg/m3). The sample collected and analyzed recorded a dioxin equivalence concentration of 0.0048 pg/m3, well below the EPA's current screening level.

Airborne Metals One common area and nine residential units were sampled for and analyzed for airborne metals (copper, lead, and chromium). All recorded analytical results were less than analytical detection limit for lead and chromium. Detectable levels of copper were detected in seven samples and were more than 1000 times lower than the best available occupational standards. There was no observed likely source recorded for the copper.

Duct and Exterior Cleaning Between December 27 and 29, 2001 TechClean Industries cleaned the supply air duct, which pressurizes the common hallway. This cleaning included removal and reinstallation after wet cleaning of the hallway grills and registers and High Efficiency Particulate Air (HEPA) vacuuming and washing of the 2 floor induction fan supplying the hallway system. The supply riser was cleaned in phases by sealing hallway diffusers with plastic sheeting and tape, deploying isolation bags to assist in controlling negative pressure, HEPA negative exhaust equipment and various pneumatic agitation devices. The work commenced from the upper most floor and worked towards the 2nd floor mechanical room. ATC collected fourteen ambient air samples, ten from within common hallways and four within the 2 floor mechanical room to ascertain the presence or absence of airborne asbestos during this cleaning. The sample methodology, quantity, and location were agreed upon between Related Management, ATC and H.A. Bader Consultants Inc. the tenants associations consultant. Samples were analyzed in accordance with the more stringent AHERA Transmission Electron Microscopy (TEM) method as set forth at 40 CFR Part 763, Subpart E, Appendix A. 5th st Based upon the analytical results from the 2 , 10`h, 15`h, 20`h 25`h 27`h 34`h, 41 floor hallways and 2nd floor mechanical room of no asbestos structures detected, which is below

NYC-WTC 000104034