Project at a Glance

Title: Experimental determination of the number and size of asbestos fibers in ambient air.

Principal Investigator / Author(s): John, Walter

Contractor: Air and Industrial Hygiene Laboratory, California Department of Health Services

Contract Number: 3-688

Topic Areas: Health Effects of Air Pollution, Stationary Sources, Toxic Air Contaminants


This investigation was designed to assess the problem which asbestos present 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 106 fibers/m3 or 104 ng /m 3 with downwind concentrations approximately 100 times 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.

This report was submitted in fulfillment of Interagency Agreement ARB-3-688 by the Air and Industrial Hygiene Laboratory, California State Department of Health, under the sponsorship of the California Air Resources Board. Work was completed as of December 31, 1975.

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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