NYC-WTC_000195194

NYC 9/11 Public Portal Document

Post P‘ Cleaning Samples - Two air samples were collected after the first cleaning. All of the samples were below the detection limit. Because all of the samples were below the detection limit after the first cleaning, no additional samples were collected for analysis of calcite.

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

Post P‘ Cleaning Samples - Two air samples were collected after the first cleaning. All of the samples were below the detection limit.

Tridymite Before Cleaning Samples - Pre-cleaning air samples were not collected. w Post P‘ Cleaning Samples - Two air samples and four wipe samples were collected after the first cleaning. All of the samples were below the detection limit.

MMVF Before Cleaning Samples - Three pre-cleaning wipe samples collected. MMVF was detected in all three.

Post P' Cleaning Samples - Three air samples and five wipe samples were collected after the first cleaning. The results for the three air samples indicate that MMVF was present; however, all samples were below the primary clearance criterion of 10 S/L. The results of the five wipe samples indicate that MMVF remained present in four of the five samples after the first cleaning, but the concentrations detected were lower than the pre-cleaning samples. There is not a clearance criterion for MMVF in settled dust. Because the air samples were substantially below the primary clearance criterion and the MMVF in settled * dust was reduced after the first cleaning, no additional samples were collected for analysis ofMMVF.

PAH Before Cleaning Samples - Three pre-cleaning wipe samples were collected. All three samples were below the detection limit. The TEF for each sample was below the primary clearance criterion.

Post P* Cleaning Samples - Four wipe samples were collected after the first cleaning. All of the samples 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.

Second Floor Hallway - The second floor hallway has vinyl tiles on the floor, and walls made of sheet rock covered with wallpaper glue. The ceiling is also made of sheet rock, and is painted.

Cleaning Method - This area was cleaned using Test 4A and Test 4B. Test 4A used an industrial

43 ills*

CITY_21MC100_011105273

NYC-WTC_000195239