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theses

Bioaerosols are airborne particulate matter of biological origin, such as microorganisms and pollen, and any particulates shed or produced by living organisms, like pet dander and mycotoxins. A wide spectrum of adverse environmental health effects can result from exposure to these particles, such as infectious or allergic respiratory diseases. To understand and mitigate the effects of bioaerosol exposures, bioaerosol sampling must be representative of the spatiotemporal scales over which the exposures occur. However, bioaerosol sampling is typically conducted with air pumps (i.e., actively) – this negatively affects the quality of the sample and limits when and where sampling can be performed. Passive sampling, on the other hand, does not need air pumps or external power, which makes it portable, cost-effective, and practical for conducting long-term sampling in any location. My dissertation aims to design, develop and evaluate a new passive bioaerosol sampler utilizing polarized, ferroelectric polymer films to enhance electrostatic collection of biological particles while streamlining sampling to analysis procedures. Specifically, I aim to: 1) conceptually design the passive sampler using parallel layers of a polarized, ferroelectric polymer film to optimize collection of microorganism-sized particles. 2) Determine extraction efficiencies of spiked microorganisms from the surface of the polymer film. 3) Optimize a field-deployable prototype sampler design using a compact, calm air settling chamber. Finally, 4) perform outdoor field testing of the passive sampler to evaluate its performance. Parallel layers of uniaxially oriented, polarized, poly(vinylidene fluoride), PVDF, with 2.25 mm wide air channels was found to significantly enhance electrostatic capture of particles in size ranges of interest for bioaerosol (~0.01 to 5 m) with varying particle surface charge. A spiral shaped prototype sampler with a 3D-printed film holder provided user-friendly sampler setup and 100% extraction efficiency of spiked microorganisms from the surface of the PVDF and the film holder material. Through outdoor field-testing, the new sampler passively collected microorganisms comparably to the active reference sampler with an equivalent sampling rate of ~2.6 L/min. and provided better preservation of microorganism culturability. Ultimately, this research presents a novel sampling tool for bioaerosol exposure assessment, a new methodological framework for bioaerosol sampler development, and new benchmarks of success for developing passive bioaerosol sampler technology.

ETD_7465

Ph.D.

Includes bibliographical references

by Jennifer Helen Therkorn

doi:10.7282/T3862JRW

ETD doctoral

The author owns the copyright to this work.