NYC-WTC_000195194

NYC 9/11 Public Portal Document

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

Calcite 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. 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. Because all of the samples were below the detection limit after the first cleaning, no additional samples were collected for analysis of cristobalite.

Tridymite 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. Because all of the samples were below the detection limit after the first cleaning, no additional samples were collected for analysis of tridymite.

MMVF Before Cleaning Samples - Four pre-cleaning wipe samples were collected. The four wipe samples had MMVF detected in concentrations from 228.93 S/cm^ to 1259.09 S/cm^. This indicates that MMVF was present prior to cleaning.

Post P‘ Cleaning Samples - Three air samples and five wipe samples were collected after the first cleaning. All of the air sample results indicate that MMVF was present but at levels below the primary clearance criterion of 10 S/L. All of the wipe sample results were at or below the detection limit of 22.89 S/cm". This indicates that the cleaning method was able to reduce the pre-cleaning concentration of MMVF.

PAH Before Cleaning Samples - Four pre-cleaning wipe samples were collected. Three of the four samples were below the detection limit and below the primary clearance criterion. The fourth sample had two PAH compounds detected; the calculated TEF was below the primary clearance criterion.

Post P‘ Cleaning Samples ~ Four post-cleaning wipe samples were collected. All four samples were below the detection limit, and each sample was below the primary clearance criterion of 300 pg/m^

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