Date of Award

Fall 1989

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Program/Concentration

Biology

Committee Director

Gerald Levy

Committee Member

David Sterling

Committee Member

Leighton Turner

Call Number for Print

Special Collections LD4331.B46 F62

Abstract

The affects of electrostatic forces on the Membrane Filter Method (MFM) used for air-borne asbestos monitoring have been investigated for many years. Several studies have indicated that these forces interfere with the collection of asbestos fibers on the membrane filter, which results in an underestimated analysis of the airborne concentration. By varying the electroconductivity of the extension cowls on the filter cassettes, it was speculated that the significance of the electrostatic forces could be statistically analyzed. Four sets of filter cassettes with grounded conductive (GC) extension cowls, ungrounded conductive (UC) extension cowls, grounded nonconductive (GN) extension cowls, and ungrounded nonconductive (UN) extension cowls were used to collect airborne asbestos samples at rates of 1.4 liters per minute and 9 liters per minute. The membrane filter from each cassette was analyzed to determine the fibers per cubic centimeter (fibers/cc) of air sampled. The cowls from each sample were then washed onto clean filters and analyzed to determine the fibers/cc collected on the cowls. The proportion of the fibers on the cowl per fibers on the original filter was calculated for each sample and the results statistically evaluated. The findings of this study indicated that a significant number of asbestos fibers were collected on the sides of all extension cowls regardless of their electroconductivity. This reduces the total number of fibers collected on the membrane filter and produces an inaccurate evaluation of the ambient airborne asbestos concentration.

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DOI

10.25777/c3mx-4w07

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