Environmentally Persistent Free Radicals, Reactive Oxygen Species and Oxidative Potential of Particulate Matter: A Case Study in Fairbanks, Alaska
SUKRITI KAPUR, Kasey Edwards, Ting Fang, Manabu Shiraiwa,
University of California, Irvine Abstract Number: 134
Working Group: Biomass Combustion: Outdoor/Indoor Transport and Indoor Air Quality
AbstractThe Alaska Layered Pollution And Chemical Analysis (ALPACA) campaign was held in January-February 2022 to understand wintertime pollution in cold and dark environments in Fairbanks, Alaska. As a part of this campaign, we conducted indoor and outdoor particle collection to study Environmentally Persistent Free Radicals (EPFRs) and Reactive Oxygen Species (ROS) production. EPFRs are long-lived species and have the ability to form ROS such as hydroxide (•OH), superoxide (O2•−), hydroperoxyl radical (HO2•), and hydrogen peroxide (H2O2). ROS are known to cause adverse impacts on human health by causing oxidative stress. We used a Tisch High-Volume sampler to collect ambient particulate matter with aerodynamic diameters less than 2.5 um (PM2.5), and a Micro-Orifice Uniform Deposition Impactor (MOUDI) to collect size-segregated particles (0.056-18 um) at a residential home where typical indoor activities such as cooking and pellet stove burning were performed. Indoor and outdoor samples were analyzed for EPFRs and ROS using an Electron Paramagnetic Resonance (EPR) Spectrometry. Oxidative potential, defined as the ability of PM to generate ROS, was quantified using the dithiothreitol (DTT) assay. Highest EPFR signal has been observed for stages with lower cutoff diameters, with concentrations ranging from 0.21± 0.11 pmol/ug for mixed (cooking & pellet stove burn) experiments, to 0.77± 0.56 pmol/ug for pellet stove burning experiments. The presence of •OH radical has been detected in the analysis for ROS. These findings will serve in a better understanding of indoor air pollution and its impacts on human health and in filling critical knowledge gaps about outdoor chemistry in sub-arctic regions.