Date of Award

Spring 2020

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Industrial Hygiene

Committee Chair

Lorri Birkenbuel

First Advisor

Julie Hart

Second Advisor

Dan Autenrieth

Third Advisor

Beverly Hartline

Abstract

Occupational exposure assessments for aerosols are commonly conducted by drawing air through a filter media, which is housed in cassette. Previous studies assessing metal and coal dust aerosol concentrations have shown a significant amount of particulate matter adhering to the inner cassette wall, thus underestimating the mass concentration reported from filter media. A common control strategy to minimize wall loss is to perform sampling with cassettes comprised of conductive material. The objective of this study was to assess the potential for cassette wall loss associated with mineral dust air sampling techniques employing conductive vs. non-conductive cassettes. Area total and respirable dust sampling was conducted in a primary rock crusher of a copper mine. In addition to analyzing the filter media, the interior of the sampling cassette was wiped with a PVC filter post sampling to quantify potential wall loss. Results revealed a significant decrease (P<0.05) in percent wall loss mass with conductive vs. non-conductive cassettes when sampling for respirable dust. A correlation was apparent (P=0.048) between wall loss mass and filter mass for conductive cassettes when using respirable dust sampling methods. However, no correlation was apparent between wall loss mass and filter mass for non-conductive cassettes when using respirable dust sampling methods. No correlation was apparent between wall loss vs. filter mass for non-conductive and conductive cassettes when applying total dust sampling. These results suggest that substantial (mass %) sample loss may occur when sampling for respirable mineral dust with non-conductive cassettes, and this wall loss may be mitigated with the use of a conductive sampling cassette.

Comments

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Industrial Hygiene

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