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Oxidative Potential of Fine Particulate Matter - Implications of Emission Source Sectors, Particle Chemical Composition and Acidity, and Metal Dissolution
POURYA SHAHPOURY, Zheng Wei Zhang, Andrea Mario Arangio, Valbona Celo, Ewa Dabek-Zlotorzynska, Tom Harner, Athanasios Nenes, Environment and Climate Change Canada
Abstract Number: 617
Working Group: Health-Related Aerosols
Abstract
Air pollution is a major global health risk. It has been associated with respiratory-cardiovascular diseases as well as increased mortality. Inhalation of particulate matter with aerodynamic diameter ≤2.5 µm (PM2.5) is a major cause of air pollution adverse effects. Oxidative potential (OP) is defined as the ability of PM-bound chemicals to oxidize the lung antioxidants either directly or through catalytic generation of reactive oxygen species. This process may result in oxidative stress, inflammation of the epithelial tissue, and chronic diseases. OP depends on various factors such as PM chemical composition and mass-size distribution. Among PM components, water-soluble organic species, quinones, and transition metals are the major contributors to OP. In this work, we investigated the OP of PM2.5 from the National Air Pollution Surveillance sites across Canada, covering urban traffic, industrial, residential, and biomass burning source sectors. We applied a novel in-vitro OP assay that we developed in-house, which considers the reaction of PM with major lung antioxidants in simulated lung lining fluid and determines the redox state of the samples. The results were evaluated through correlation analysis with PM2.5 constituents including organic matter, black carbon, transition metals, biomass-burning markers, organic ligands, as well as the aerosol pH. Our findings indicate that PM2.5 oxidative burden was influenced by the emission source sectors, with traffic emission having the highest activity followed by industry and biomass burning. Water-soluble metals and black carbon were the major contributors to OP, with the former being influenced by the levels of aerosol-bound oxalate as well as pH in the aerosol aqueous phase. This study provides an insight into how current trends in urbanization and anthropogenic activities, as well as various emission sources, contribute to PM composition, human exposure and health risks associated with fine inhalable PM.