The Interrelationships of Selected Asbestos Exposure Indices (1970)

This industrial hygiene study, part of a United States Public Health Service epidemiological study of the asbestos products industry, compared ways of measuring airborne asbestos dust. Using almost 10,000 air samples from the manufacture of asbestos textile, friction, cement and insulation products, the authors compared impinger dust counts, fiber counts on membrane filters under phase-contrast light microscopy, electron microscope counts, and dust weights, including chrysotile estimated from magnesium. Impinger counts and membrane filter fiber counts correlated weakly, with coefficients not over 0.6, and in pipe plants they did not correlate significantly. Electron microscopy showed that only a small proportion of fibers were over 5 microns long, and its results were heavily weighted toward very small fibers. For the same total or respirable dust concentration, the asbestos fiber concentration could differ by a factor of 10 depending on the product area. The authors concluded that the most convenient, practical and direct index of asbestos fiber exposure was the concentration of fibers longer than 5 microns counted on membrane filters at 430X phase-contrast illumination.

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From J-M's medical library

This copy comes from the Johns-Manville medical library. J-M listed it in its medical library index as no. 004951.