NYC-WTC_000231976

NYC 9/11 Public Portal Document

Section 2 - Ambient Air Monitoring Program Revision No.: 0 130 Liberty Street Deconstruction Plan Date: September 7, 2005 Lower Manhattan Development Corporation

6.0 SAMPLING FREQUENCY 6.1 Background

The background ambient air sampling period will consist of two weeks (14 consecutive calendar days) of monitoring performed immediately prior to the start of Phase I - Preparation Phase activities. Samples will be collected at the four (4) ground level stations in the monitoring network (Locations 1-4 in Table 1) and one (1) station located on the roof of the Fire Station situated at 124 Liberty Street (FDNY 10-10 House). All target parameters will be collected over a 24-hour integrated period with the exception of asbestos, silica, PMio, PM2.5, and mercury utilizing the Lumex instrument. PMioand PM2.5 will be monitored continuously at each of the five (5) sites while asbestos and silica measurements will be taken at a frequency of once per work shift at each of the sites.

6.2 Phase 1 - Preparation Phase

The Phase I - Preparation Phase air monitoring will follow the schedule and frequency as described below and will commence with the start of Preparations Phase site work.

During the first three (3) days only of Phase I Preparation Phase work, samples will be collected and analyzed for semivolatile organics to include PCDDs/PCDFs, PAHs and PCBs. After this first three (3) day period, sampling for semivolatile organics will be reduced to a once per week frequency employing the entire station network. One day per week on a rotating basis (week #1 Monday, week #2 Tuesday, etc.) samples will be collected at every station in the network. The schedule will be repeated until project completion.

The semivolatile organic samples collected employing this sampling frequency will not be processed for analyses; rather they will be placed in archival storage at the laboratory. A single set of samples will be selected from each weekly sampling event to undergo analyses for PCDDs/PCDFs, PAHs and PCBs. The station with the highest 24-hour average PMio concentration (ug/m3) recorded with a collocated organic sample each week will be selected for semivolatile organic analyses.

Roof Cleaning: four (4) ground level stations and one (1) off-site elevated station (Locations 1-5 in Table 1) and four (4) rooftop locations. Target parameters for these stations will follow those presented in Section 4.

Scaffold Erection and associated tasks: Scaffold erection up to and including completion of scaffold work on the 10**' Floor - four (4) ground level stations and one (1) off-site elevated station (Locations 1-5 in Table 1). Target parameters and the frequency of sample collection for these stations will follow those presented in Section 4. Once the scaffold erection work is completed on the 10* floor, seven (7) additional stations (Locations 6-12) will be installed. Target parameters for these additional stations will follow measures presented in Section 4. As

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NYC-WTC_000231994