NYC-WTC_000152801

NYC 9/11 Public Portal Document

V. Residence Selection/Sampling Rationale

The selection of priority residential areas should be decided upon by NYC DOH or the agency of their choosing, or by someone else on the scene with the concurrence of NYC DOH. Currently, NYCDOH is proposing approximately 60 residential units be sampled. Locations are being selected based on worst-case scenario(s) first, which will likely involve a visual determination (e.g., visible dust in lobby area, broken windows, dust along roadways and sidewalks). Worst­ case residential areas would include:

This section will change based on input of priorities: A. Occupied [delete...and unoccupied] residential areas closest to the WTC with visible exterior dust/fallout material B. Residential areas further from the WTC, where debris fallout may be tracked indoors C. In-use commercial areas near the WTC, where visible dust is present D. delete... [Residential areas where Search/Rescue/Removal vehicles have spread dust that may be tracked indoors]

Once locations are selected, then sampling can be pursued. Need to discuss/determine if sampling will be conducted in unoccupied residences. If results in worst-case locations show indoor contamination/materials present at levels of concern, a thorough cleaning (these instructions need to be developed) should follow and the locations should be re-sampled. If the post-cleaning round of sampling indicates successful cleaning, then a thorough cleaning should be conducted prior to sampling any additional locations. If post-sampling confirms that contaminants are below levels of health concern, then as other residential areas are cleaned, post­ cleaning sampling should occur periodically as a quality assurance check of cleaning effectiveness.

It should be noted that contaminant/materials of concern may vary as the distance of the residence increases from the WTC.

If results of outdoor testing show contamination/materials present at levels of concern, efforts should be made to reduce these levels and take steps that eliminate transporting them indoors (e.g,. reduce contaminant track in by removing or changing shoes prior to entering residence, use HEPA filters on HVAC systems, keep windows closed).

VI, Sampling Approach;

1. Interior Air and dust sampling should focus on common/high traffic areas of the building (e.g., lobbies, front entryways) and in a selected number of apartments/units where visible dust is and is not reported. These areas should be representative of worst case conditions for contaminant/material track-in from outdoors and for fallout deposition. Selecting apartments/units in the same building should provide informatir,.; the ranges found in indoor living spaces.

[delete...If the building is unoccupied, aggressive (leaf blower, high-power fan) indoor air sampling should be conducted.] If the building is occupied, air sampling should be conducted with the building HVAC system in continuous operation. After sampling is completed, filters for

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