Reactive Oxygen Species in Biomass Burning Particles: Dependence on Chemical Composition and Photochemical Aging

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The Environmental Chemical Sciences Program in the Division of Chemistry supports Professors Manabu Shiraiwa and Sergey Nizkorodov for studies of biomass burning aerosols. Biomass burning is an important source of atmospheric particulate matter in the era of global climate change, as the frequency and intensity of wildfires have been increasing. Biomass burning organic aerosol (BBOA) particles contain various redox-active compounds, which can trigger the formation of reactive oxygen species (ROS) that play a central role in chemical transformation of organic compounds in the atmosphere. For better assessment of BBOA influence on air quality and climate, a molecular-level and mechanistic understanding of ROS multiphase chemistry and photochemistry by BBOA particles is needed. Graduate and undergraduate students will be involved in this research. Minority junior high school students will be hosted with a seminar on biomass burning aerosols and hands-on experiments to stimulate their interests on environmental chemical sciences.The project aims at elucidating chemical mechanism and kinetics of ROS formation from redox-active components in BBOA particles. Electron paramagnetic resonance spectroscopy will be applied to quantify the formation of ROS in BBOA surrogate mixtures and BBOA generated by pyrolysis and smoldering combustion of biomass samples. Chemical composition of BBOA particles will be characterized using an ultra-high-performance liquid chromatograph coupled to a high-resolution mass spectrometer. Impacts of photochemical aging on formation of ROS will be assessed to advance mechanistic understanding of BBOA aging processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.