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Comparison of three methods to convert Chinese mining dust exposure into respirable fraction.

Gao-P; Chen-B; Hearl-F; Schwerha-D; Zhuang-Z; Soderholm-S; Chen-W; Chen-J
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :19
There is a rich historical Chinese total dust database being used in an ongoing joint Chinese/NIOSH epidemiological study to clarify the exposure-response relationship for the development of silicosis. In order to apply these data to American standards, conversion factors are needed between historically measured Chinese total dust data and respirable dust levels. In 1988, as a part of this collaboration, airborne dust samples were collected side-by-side in 20 metal mines and 9 pottery factories in China using nylon cyclones, multistage "cassette" impactors and filters. Total dust concentration was gravimetrically measured based on the Chinese dust sampler, and particles on its filter were sized microscopically. The study yielded three different estimates of the conversion factor from Chinese total dust to respirable dust (1) the ratio of respirable concentration by cyclone to the Chinese total dust concentration (geometric mean 0.363), (2) the ratio of respirable concentration by impactor to the total dust concentration (geometric mean 0.229), and (3) the values calculated by using the Hatch-Choate equation based on the microscopic sizing data (geometric mean 0.032). Multiple analyses of variance (MANOVA) reveals that, with a fixed sampling/analysis method, respirable fractions were not significantly different among the different job titles within each industry. MANOVA also indicates that respirable fractions among the mines and industries were not significantly different when the cyclone or impactor measuring data were used, but were significantly different when the microscopic data were used, being significantly lower in the pottery industries (p value=0.048). Thus, it is concluded that conversion factors estimated from different methods are quite different.
Analytical-methods; Analytical-instruments; Mining-industry; Dusts; Dust-particles; Respirable-dust; Standards; Air-sampling; Air-sampling-equipment; Air-sampling-techniques; Metal-dusts; Metal-mining; Pottery-industry; Sampling-equipment; Sampling-methods; Dust-samplers; Dust-sampling; Filters; Gravimetric-analysis; Microscopic-analysis; Cyclone-air-samplers
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American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia