Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Program Name/Specialization

Environmental Science

Faculty/School

Faculty of Science

First Advisor

Dr. Sarah Poynter

Advisor Role

Biological methodology, interpretation, and application, review and revision of the dissertation

Second Advisor

Dr. Lucas Neil

Advisor Role

Methodological, structural, and research design guidance; critical review, editing, and revision of the dissertation, including research framing and presentation.

Abstract

Air pollution remains one of the most persistent environmental stressors affecting human health in urban environments. Fine particulate matter (PM2.5), due to its small aerodynamic diameter and efficient deposition in the alveolar region of the lungs, acts as a chemically active environmental interface and plays a central role in respiratory and cardiovascular disease. This research presents an investigation of the chemical composition and biological content of urban aerosol particles in the Waterloo Region of Ontario. Despite being one of Canada's fastest growing mid-size urban regions, Waterloo has limited chemically and size resolved aerosol data needed to characterize local conditions under routine and episodic pollution conditions. The experimental framework comprised three integrated components: (1) Complementary aerosol collection using two instruments: size resolved Micro Orifice Uniform Deposition Impactor and Particle into Liquid Sampler. (2) Quantification of the oxidative potential and chemical analysis of the collected particles via dithiothreitol, inductively coupled plasma optical emission spectrometry, and total organic carbon analyzer. (3) Identification of the airborne biological content of deoxyribonucleic acid extracts via real-time polymerase chain reaction. Method development established a Dithiothreitol (DTT) reactivity among the three quinones tested, with fitted concentration-response slopes of 6.49 min-1 for phenanthrenequinone, 2.04 min-1 for 1,2-naphthoquinone, and 0.30 min-1for 1,4-naphthoquinone. For the ambient samples, median volume normalized oxidative potential was 64.97 pmol min-1m-3 in 2023 (n = 5) and 131.00 pmol min-1 m-3 in 2024 (n = 20). Among the five 2024 atmospheric regimes, the summer mixed urban regime had the highest median PM2.5 and organic carbon concentrations, at 17.00 and 17.90 mg m-3 , respectively, whereas the highest median DTT oxidative potential occurred during summer good background regime at 172.60 pmol min-1 m-3. Thus, within the 2024 regime analysis, the regime with the highest particle and soluble carbon loading was not the regime with the highest oxidative potential. The biological measurements also showed a wide event to event range, with 16S rRNA gene abundance in the 2024 samples spanning 7.06 × 104 - 1.50 × 108 copies m-3. This study provides the first integrated dataset characterizing PM2.5 chemical speciation, redox activity, and bioaerosol presence in Waterloo Region. The significance of this work lies in establishing a transferable blueprint for conducting similar assessments in other regions where detailed monitoring infrastructure is limited. By supporting consistent cross regional comparisons, this approach improves interpretation of spatial variability in PM2.5 composition and associated properties across urban microenvironments. This provides a scientific basis for government officials to develop targeted policies and educational material to minimize the impact of air pollutants on citizens in different neighborhoods.

Convocation Year

2027

Convocation Season

Spring

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Available for download on Wednesday, March 22, 2028

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