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)

TABLE II—SUMMARY OF SAMPLING AGENCY DATA QUALITY OBJECTIVES

This table summarizes the data quality objectives from the performance of this method in terms of precision, accuracy, completeness, representativeness, and compiability. These objectives are assured by the periodic control checks and reference checks listed here and described in the text of the method. CUifflimance UniiODeraiion PC Check Frequency Exneetnfifln

Sampling materials Sealed blank Iper I/O site 95% Sample procedures Field blanks 2 per WO site 95% Pump calibration Before and after each field series 90% Sample custody Review of chain-of-cusiody record Each sample 95% complete Sample shipment Review of sending repon Each sample 95% complete

C. Sample Shipment a. TEM Grid Opening Area measurement must be done as follows: Ship bulk samples to the analytical lab­ 1. The filter portion being used for sample oratory in a separate container from air samples. preparation must have the surface collapsed using an acetone vapor technique. D. Sample Receiving 11. Measure 20 grid openings on each of 20 random 200-mesh copper grids by placing a 1. Designate one individual as sample coor­ grid on a glass and examining it under the dinator at the laboratory. While that indi­ PCM. Use a calibrated graticule to measure vidual will normally be available to receive the average field diameters. From the data, samples, the coordinator may train and su­ calculate the field area for an average grid pervise others in receiving procedures for opening. those times when he/she Is not available. ill. Measurements can also be made on the 2. Bulk samples and air samples delivered to the analytical laboratory In the same con­ TEM at a properly calibrated low magnifica­ tainer shall be rejected. tion or on an optical microscope at a mag­ nification of approximately 400X by using an E. Sample Preparation eyepiece fitted with a scale that has been calibrated against a stage micrometer. Opti­ 1. All sample preparation and analysis cal microscopy utilizing manual or auto­ shall be performed by a laboratory inde­ mated procedures may be used providing In­ pendent of the abatement contractor. strument calibration can be verified. 2. Wet-wipe the exterior of the cassettes to b. TEM specimen preparation from minimize contamination possibilities before polycarbonate (PC) filters. Procedures as de­ taking them Into the clean room facility. scribed in Unit III.G. or other equivalent 3. Perform sample preparation in a well- methods may be used. equipped clean facility. SNote: The clean area Is required to have c. TEM specimen preparation from mixed the following minimum characteristics. The cellulose ester (MCE) filters. area or hood must be capable of maintaining 1. Filter portion being used for sample a positive pressure with make-up air being preparation must have the surface collapsed HEPA-filtered. The cumulative analytical using an acetone vapor technique or the blank concentration must average less than Burdette procedure (Ref. 7 of Unit II.J.) 18 s/mm^ In an area of 0.057 mm’ (nominally li. Plasma etching of the collapsed filter Is 10 200-mesh grid openings) and a single prep­ required. The microscope slide to which the aration with a maximum of 53 s/mm’ for collapsed filter pieces are attached is placed that same area. in a plasma asher. Because plasma ashers 4. Preparation areas for air samples must vary greatly in their performance, both from not only be separated from preparation areas unit to unit and between different positions for bulk samples, but they must be prepared in the asher chamber, it is difficult to speci­ in separate rooms. fy the conditions that should be used. Insuf­ 5. Direct preparation techniques are re­ ficient etching will result in a failure to ex­ quired. The object is to produce an intact pose embedded filters, and too much etching film containing the particulates of the filter may result In loss of particulate from the surface which is sufficiently clear for TEM surface. As an Interim measure, it is rec­ analysis. ommended that the time for ashing of a

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NYC-WTC_000139289