Experimental Determination of the Number and Size of Asbestos Fibers in Ambient Air.

摘要

This investigation was designed to assess the problem which asbestos presents as a community air pollutant by quantifying asbestos fibers in ambient air near a mill. An array of samplers and wind sensors were operated during two periods with different prevailing wind directions. The Nuclepore filter samples were analyzed by transmission electron microscopy using a direct clearing method of sample preparation which was adapted to this work. Asbestos fiber concentrations ranged up to 1,000,000fibers/cu m or 10,000ng/cu m with downwind concentrations approximately 100times greater than those upwind. Large tangles of asbestos occurring due to the proximity of the source were excluded from the analysis. The size distributions indicated that fibers shorter than the pore size penetrated the filters. The principal source of the emissions appeared to be windblown material from open ore and tailing piles.