VOC sampling locations table for Ground Zero area, Jan 2002

NYC 9/11 Public Portal Document

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Figure 4. SEM/EDX results from water-extracted lyophilized WTC PM samples. The upper-left quadrant of each photomicrograph shows a field of view with the particle of interest within the smaller square in that field. The upper-right quadrant shows a zoomed-in view of the feature (the area from within the square in the upper-left quadrant), and the lower half shows the elemental spectrum acquired with the electron beam centered on the small (barely visible) square in the zoomed-in view. A. Example of Ca-S crystal which dominated the samples. B. Example of fine particle aggregate which was prominent in the samples. C. Example of fiber found in the samples. D. Example of metallic particle within fine particle aggregate.

consistent with the ICP data which show water-soluble prominent (Figure 4B). Fibers approximately 1 pm in calcium and sulfate in the same proportions as gypsum. diameter were found in most of the samples and had a Gypsum is completely water-soluble at the solid/liquid composition similar to the fine particle aggregates (Figure ratio of the extraction conditions used in the ICP analysis, 4C). Metallic particles (mostly Ti and Fe, though Zn, Pb, while calcite is not water-soluble. The sample of MSH Ba, and Cu were also found) were found typically as was also analyzed by XRD and the results were consistent inclusions in the large fine particle aggregates (Figure 4D). with those previously reported (Graham et al., 1985; data The crystals and aggregates were likely not original to the not shown). bulk sample but were formed as a result of the aqueous 5. SEM/EDX analysis. Water-extracted and extraction process. lyophilized WTC PM samples were dominated by SEM/EDX analysis of the aerosolized PMj s cut snowflake-like crystals composed of calcium and sulfur fraction of WTC3 showed the same overall chemistry as (Figure 4A). Aggregates of fine particles composed of the extracted and lyophilized WTC PM samples: the various combinations of Mg, Al, Si, S, and Ca were also majority of particles were composed of Ca or Ca-S, some

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