NYC-WTC_000195194

NYC 9/11 Public Portal Document

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WK the detection limit. «r Tridymite Before Cleaning Samples - Pre-cleaning air samples were not collected.

Post P‘ Cleaning Samples (T3st 4A) - Two air samples were collected. Both air samples were below the detection limit. . w Post P‘ Cleaning Samples (Tast 4B) - Two air samples were collected. Both samples were below the detection limit. * «r Post P‘ Cleaning Samples (Test 4C) - Two air samples were collected. Both were below IV the detection limit. IV MMVF Before Cleaning Samples - Four air samples and three wipe samples were collected. All four air samples were above the detection limit. MMVF was detected above the primary clearance criterion of 10 S/L in two of the four air samples. The three wipe samples had detectable concentrations of MMVF.

Post T‘ Cleaning Samples (Test 4A) - Three air samples and four wipe samples were collected. MMVF was present in all, but at concentrations below the primary clearance criterion of 10 S/L. All of the wipe sample results were below the concentrations detected during pre-cleaning sampling, with one below the detection limit.

Post T‘ Cleaning Samples (Tsst 4B) - Three air samples and four wipe samples were collected after the first cleaning. All three of the air samples were below the primary clearance criterion of 10 S/L. All of the wipe samples were below the concentrations detected during pre-cleaning sampling, with one below the detection limit.

Post T* Cleaning Samples (Test 4C) - Five air samples were collected after the first cleaning. MMVF was present in all, but at concentrations below the primary clearance criterion of 10 S/L.

Post P‘ Cleaning Samples (Test 4D) - Three air samples were collected after cleaning. All were below the detection limit and below the primary clearance criterion of 10 S/L.

If PAH Before Cleaning Samples - One air sample and three wipe samples were collected. The air sample was below the detection limit. The TEF was below the primary clearance criterion of 0.2 pg/m^. Two of the three wipe samples had PAH compounds detected. One sample detected three PAH compounds and the other detected two PAH compounds. The calculated TEFs for these two samples, as well as the third sample, were below the primary clearance criterion of 300 pg/nY.

Post P‘ Cleaning Samples (Pest 4A) - Four post-cleaning wipe samples were collected. All four were below the detection limit; the TEF for each sample was below the primary

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NYC-WTC_000195297