Abstract View
Reactive Oxygen Species in Fresh and Aged Biomass Burning Organic Aerosol
Shunyao Wang, Carolyn Liu-Kang, Jonathan Abbatt, Peter Gallimore, ARTHUR W. H. CHAN, University of Toronto
Abstract Number: 424
Working Group: Health-Related Aerosols
Abstract
Biomass burning is an emerging issue all over the world in recent decades, threatening global climate and human health. The dynamic toxicity of biomass burning organic aerosol (BBOA) upon atmospheric processing remains poorly understood. For the first time, oxidative potential (OP) of primary and aged organic aerosol (by heterogenous OH oxidation) from wood burning were investigated by the dithiothreitol assay (DTT). In parallel, electron paramagnetic resonance (EPR) was applied to the direct measurement of reactive oxygen species (ROS) in primary and aged biomass burning aerosol. Results showed that the OP of organic aerosol from biomass burning is significantly enhanced upon aging equivalent to less than one day of oxidant exposure. Consistent with acellular OP measured by DTT, EPR ROS quantification using different spin trap techniques also showed a higher abundance of ROS in aged BBOA. After applying radical speciation and spin fitting, carbon centered radicals were found to be the most abundant radical species in primary organic aerosol from biomass burning while oxygen-centered radicals were found to be the dominant ROS in BBOA during atmospheric aging. Detailed chemical characterization performed by the high-performance liquid chromatography-high resolution mass spectrometer (HPLC-HRMS) illustrated that primary BBOA is predominantly consisted of less oxygenated multi-ring aromatic compounds while aged BBOA presents significantly higher abundance of oxygenated aromatic compounds with an elevated oxygen to carbon ratio, which contributes to an enhanced level of particle-bound ROS.