Forwarding WTC air monitoring scope for final review, Aug 2002

NYC 9/11 Public Portal Document

Pt. 763, Subpt. E. App. A 40 CFR Ch. I (7-1-00 Edition) B, Sampling concentrations of asbestos which may inter­ fere with the analysis of the sample. A filter 1. The sampling agency must have written blank average of less than 18 s/mm’ in an quality control procedures and documents area of 0.057 mm^ (nominally 10 200-mesh grid which verify compliance. openings) and a single preparation with a 2, Sampling operations must be performed maximum of 53 s/mm^ for that same area Is by qualified individuals completely inde­ acceptable for this method. pendent of the abatement contractor to 5. Use sample collection filters which are avoid possible conflict of interest (Ref­ either polycarbonate having a pore size less erences 1, 2, 3. and 5 of Unit II.J,), than or equal to 0.4 gm or mixed cellulose 3. Sampling for airborne asbestos following ester having a pore size less than or equal to an abatement action must use commercially 0.45 gm. available cassettes. 6. Place these filters in series with a 5.0 gm 4. Prescreen the loaded cassette collection backup filter (to serve as a diffuser) and a filters to assure that they do not contain support pad. See the following Figure 1:

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NYC-WTC_000139285