NYC-WTC_000232249

NYC 9/11 Public Portal Document

2.0 SAMPLING SITES 2.1 Network Design

Due to the unique circumstances associated with this deconstruction project two different types of monitoring sites are recommended for inclusion in the active monitoring network as follows:

• Street Level Stations- These locations essentially represent sidewalk settings situated around the perimeter of the building.

• Upper Level Stations- While extremely unlikely, it is not impossible for dusts to be released during building deconstruction at upper levels of the 40-story structure.. Accordingly, the proposed network will make use of a number of monitoring sites in place at elevated locations above street level. Three (3) such stations will be included in the monitoring network as shown in Figure 1.

2.2 Siting Criteria and Network Operations

The proposed network will be comprised of seven (7) stations in simultaneous operation at all times that building deconstruction activities are in progress, four (4) street level and three (3) elevated. The placement of sampling stations will follow USEPA and United States Army Corps of Engineers (ACOE) siting criteria for ambient particulate sampling systems to the extent possible. Strict adherence to these criteria at all stations may not be possible given the topography and logistics of the urbanized environment characteristic of the Uower Manhattan setting.

All four (4) of the ground level stations in the vicinity of the deconstruction site will be connected to a central computer housed in the site vicinity. The three (3) stations situated at elevated sites above street level will collect data continuously and telemeter (wirelessly transmit) the data to the central computer. All seven (7) of the monitoring stations in the immediate vicinity of the deconstruction site will monitor particulate as PM 10 on a real-time basis. These data will be logged continuously at each of the sites as well as on the data logger contained in the on site computer center. These data will be stored and archived as 5-minute averages for each of the seven (7) stations.

2.3 Locations of Monitoring Stations

The list of proposed monitoring locations is provided in Table 1. These include four (4) stations situated at ground or street level and three (3) stations situated at elevated locations atop buildings adjacent to the 130 Liberty Street property. Actual stations pending access will be placed on roof-tops or setbacks of buildings directly across the street along the perimeter of the deconstruction site. The approximate locations of each of these stations in relation to the 130 Liberty Street Site are shown in the site schematic provided as Figure 1. Figure 1 also includes a composite wind rose representative of the New York Metropolitan area noting predominant wind directions likely to be characteristic of the project work zone during the term of the

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NYC-WTC_000232255