Ambient Dust Sampling Protocol Near WTC, Oct 2001

NYC 9/11 Public Portal Document

***WRAFT Version 10, October 29, 2001****

V. Residence Selection/Sampling Rationale

The selection of residential sampling locations will be decided upon by NYC DOH. The general NYCDOH approach is described as follows: A total of approximately 60 residential units will be sampled (a unit is an individual apartment or a common area in a multi-apartment building). A series of three concentric circles is bei.ig drawn around the WTC location. These circles will be divided by direction or zone from the WTC (north, south and west, and east). From five to seven of the multi-residential ’buildings will be selected for testing fi-om within each zone.

Testing locations will mainly focus on occupied residences. However, approximately five unoccupied units nearest the WTC will be targeted for testing. In addition, approximately ten units will be selected outside of the concentric circles, in neighboring boroughs or communities, to serve as background sample locations.

Sampling personnel will document the rationale for selecting buildings and residential units for sampling. They will also document sample locations, conditions during sampling, and possible interfering factors (e.g., traffic, construction). In addition, unit occupants and building owner/operators will be requested to provide information that will better assist in evaluating the results. Section VII of this plan contains the information needed/requested.

It should be noted that types of contaminant/materials and their concentrations may vary as the distance of the residence fi-om the WTC increases.

VL Sampling/Analysis Approach:

1.Indoor

Air and dust sampling will focus on both common/high traffic areas of the building (e.g., lobbies, fi-ont entryways) and on a selected number of apartments/units in the building. Attempts will be made to select apartments/units where dust is visible as well as units where dust is not visible. Selecting entryways and common areas should be representative of worst case conditions for contaminant/material track-in from outdoors. Selecting several apartments/units in the same building-with and without visible dust—should provide information on the ranges of contaminants found in indoor living spaces.

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/unit HVAC system’s fan in continuous operation. After sampling is completed, filters for the HVAC system, if applicable, should be inspected. If dust is present, recommend filter replacement.

Indoor air sampling for asbestos will be conducted and analyzed using NIOSH method 7400. If an action level is exceeded subsequent filter analysis using NIOSH 7402 to determine if the fibers present are asbestos will be conducted. Respirable crystalline silica will be sampled and analyzed using NIOSH method 7500. Air sampling for inhalable, thoracic, and respirable size

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