EGU23-10454
https://doi.org/10.5194/egusphere-egu23-10454
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Sulfate aerosol formation mechanisms constrained by oxygen and sulfur isotopes at coastal Hong Kong

Qianjie Chen1, Allison Moon2, Andrew Schauer2, Tao Wang1, and Becky Alexander2
Qianjie Chen et al.
  • 1Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China
  • 2Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA

Sulfate plays a key role in the formation and growth of aerosol particles and cloud droplets in the troposphere and is thus important for air quality and climate. The formation mechanisms of sulfate vary with oxidant levels and environmental conditions and can be partially revealed by its isotopic signatures. Here we measure oxygen (16O, 17O, 18O) and sulfur isotopes (32S, 34S) of the sulfate aerosol samples collected at coastal Hong Kong, downwind of the highly urbanized Pearl River Delta region. Based on ion measurements, most (95%) of the sulfate collected is non-sea-salt sulfate. The δ34S of sulfate is on average 4.0±2.0 ‰ (range 0.7 – 8.0 ‰), at an average sulfur oxidation ratio of 79±9%. The average oxygen-17 excess (Δ17O) is -0.1±0.3 ‰, suggesting an important role of OH / transition metals / reactive halogens. The δ18O of sulfate is on average 4.9±2.1 ‰. The Markov-Chain Monte Carlo model will be used to further constrain sulfate formation mechanisms.

How to cite: Chen, Q., Moon, A., Schauer, A., Wang, T., and Alexander, B.: Sulfate aerosol formation mechanisms constrained by oxygen and sulfur isotopes at coastal Hong Kong, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10454, https://doi.org/10.5194/egusphere-egu23-10454, 2023.