NYC-WTC_000195194

NYC 9/11 Public Portal Document

Tridymite Before Cleaning Samples - Pre-cleaning air samples were not collected.

Post P‘ Cleaning Samples - Two air samples were collected after the first cleaning. One was below the detection limit and one was slightly above the detection limit.

MMVF Before Cleaning Samples - Three pre-cleaning wipe samples were collected. All three samples were above the detection limit.

Post P‘ Cleaning Samples - Three air samples and five wipe samples were collected after the first cleaning. The results indicate that MMVF was present in all three, with two samples being above the primary clearance criterion of 10 S/L. The third was below the primary clearance criterion. The results of the five wipe samples indicate that MMVF was still present after the first cleaning at concentrations similar to or higher than the pre­ cleaning samples. There is not a clearance criterion for MMVF in settled dust; however, since two of the air samples were above the primary clearance criterion, additional air samples were collected for analysis of MMVF.

Post 2^ Cleaning - Five air samples were collected after the third cleaning. The results indicate that the two of the five samples were above the primary clearance criterion. Due to this situation, additional air samples were collected after the third cleaning.

Post 3^ Cleaning - Two air samples were collected after the second cleaning. The results indicate that both samples were below the primary clearance criterion and below the detection limit.

PAH Before Cleaning Samples - Three pre-cleaning wipe samples were collected. Two of the three samples were below the detection limit; the TEF for these samples was below the primary clearance criterion. The third sample had four PAH compounds detected; the calculated TEF was 303.5 pg/m^ which is slightly above the primary clearance criterion of 300 pg/m’.

Post P‘ Cleaning Samples - Four wipe samples were collected after the first cleaning. All were below the detection limit. The TEF for each sample was below the primary clearance criterion of 300 pg/m^. Since all of the samples were below the detection limit and the primary clearance criterion after the first cleaning, no additional samples were collected for analysis of PAH.

Unit 5D - This unit is on the fifth floor. It is a 1,024 sq. ft. open loft facing the World Trade Center site. This unit had windows that were blown in, which resulted in significant dust accumulation. The dwelling has hardwood floors with no carpet. All personal items were removed prior to cleaning.

Cleaning Method ~ This unit was cleaned using Test 3B; an industrial HEPA-filtered vacuum and

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