|Address:||G5703, 5/F, Yeung Kin Man Academic Building (YEUNG),
City University of Hong Kong,
Tat Chee Avenue, Kowloon, Hong Kong SAR
Department of Chemistry
University of Toronto
Atmospheric sulfate aerosols have important impacts on air quality, climate, and human and ecosystem health. However, current air-quality models generally underestimate the rate of conversion of sulfur dioxide (SO2) to sulfate during severe haze pollution events, indicating that our understanding of sulfate formation chemistry is incomplete. This may arise because the air-quality models rely upon kinetics studies of SO2 oxidation conducted in dilute aqueous solutions, and not at the high solute strengths of atmospheric aerosol particles. Here, we utilize an aerosol flow reactor to perform direct investigation on the kinetics of aqueous oxidation of dissolved SO2 by hydrogen peroxide (H2O2) using pH-buffered, submicrometer, deliquesced aerosol particles at relative humidity of 73 to 90%. We find that the high solute strength of the aerosol particles significantly enhances the sulfate formation rate for the H2O2 oxidation pathway compared to the dilute solution. By taking these effects into account, our results indicate that the oxidation of SO2 by H2O2 in the liquid water present in atmospheric aerosol particles can contribute to the missing sulfate source during severe haze episodes.
Dr. Tengyu Liu obtained his BSc in Environmental Engineering from Xi’an Jiaotong University in 2010 and Ph.D. in Environmental Science from Guangzhou Institute of Geochemistry, Chinese Academy of Sciences in 2015. He is currently a postdoctoral fellow at the Department of Chemistry, University of Toronto. Prior to joining the UofT, he worked as a postdoctoral fellow at City University of Hong Kong. His current research focuses on the S(IV) oxidation in wet aerosols.