NYC 9/11 Public Portal Document
Post Cleaning Samples (Test 4D) - Two air samples were collected. Both were below the
detection limit of 0.052 pg/m^ and the primary clearance criterion of 1.0 pg/m’.
Post P‘ Cleaning Samples (Tsst 4E) - Three wipe samples were collected. Two of the
three samples were below their respective primary clearance criterion. The third sample
exceeded the primary clearance criterion of 25 pg/ft^ at a concentration of 954 pg/ft^.
Alpha-Quartz
Before Cleaning Samples - Pre-cleaning air samples were not collected.
Post P‘ Cleaning Samples (Test 4A) - Two air samples were collected after the first
cleaning. Samples were below the detection limit.
Post P^ Cleaning Samples (Test 4B) - Two air samples were collected. Samples were
below the detection limit.
Post 1" Cleaning Samples (Test 4C) - Two air samples were collected. Both were below
the detection limit.
Calcite
Before Cleaning Samples - Pre-cleaning air samples were not collected.
Post P* Cleaning Samples (Test 4A) -Two air samples were collected after the first
cleaning. Samples were below the detection limit.
Post P‘ Cleaning Samples (Tsst 4B) - Two air samples were collected. Samples were
below the detection limit.
Post P‘ Cleaning Samples (Test 4C} - Two air samples were collected. Both were below
the detection limit.
Cristobalite
Before Cleaning Samples - Pre-cleaning air samples were not collected.
Post Cleaning Samples (Test 4A} - Two air samples were collected after the first
cleaning. Both samples were below the detection limit.
Post P^ Cleaning Samples (Test 4B) - Two air samples were collected. Both samples
were below the detection limit.
Post P‘ Cleaning Samples (Test 4C) - Two air samples were collected. Both were below
the detection limit.
Tridymite
Before Cleaning Samples - Pre-cleaning air samples were not collected.
Post P* Cleaning Samples (Test 4A) -T'wo air samples were collected after the first
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NYC-WTC_000145785
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