Niu Zhengwen, Lin Mang
State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100039, China.
ACS Environ Au. 2024 Dec 19;5(3):267-276. doi: 10.1021/acsenvironau.4c00070. eCollection 2025 May 21.
Natural and anthropogenic emissions of sulfur-bearing species significantly alter the sulfur and energy budgets of the Earth's atmosphere. Simulations of the atmospheric sulfur cycle, sulfate radiative forcing, and predictions of their future changes require a precise understanding of the SO oxidation rates that control the formation of secondary sulfate aerosols. Given the unique single source of radiosulfur (cosmogenic S radionuclide), combined measurements of atmospheric radiosulfur in both sulfur dioxide (SO) and sulfate (SO ) have been employed to constrain sulfur oxidation rates in the atmosphere. This approach employed box model calculations, incorporating several key assumed parameters, including sulfur deposition rates. However, previous calculations did not fully consider uncertainties in parametrizations, necessitating a re-examination of the estimated values. In this study, we applied a new approach to revisit existing combined measurements of SO and SO at coastal and inland sites. We estimated the temporospatial variability in SO oxidation rates by incorporating a comprehensive consideration of parametrization uncertainties. We adopted deposition data from nine models of the Atmospheric Chemistry and Climate Model Intercomparison Project. Uncertainties in deposition data and other key parameters, such as cosmogenic S production rates and SO/SO ratios in the free troposphere, were evaluated by using a Monte Carlo approach. Our new analysis reveals higher SO oxidation rates than previously estimated, consistent with recent multiphase kinetics studies. Additionally, the potential relationship between changes in SO oxidation rates and sulfate formation pathways was elucidated by comparing these results to sulfate oxygen-17 anomalies. Our approach and findings offer a stringent assessment of how various sulfate formation pathways contribute to the overall SO oxidation rate in the planetary boundary layer and are therefore useful for evaluating the impacts of the atmospheric sulfur cycle on environmental health, public health, and climate.
含硫物种的自然和人为排放显著改变了地球大气的硫和能量平衡。对大气硫循环、硫酸盐辐射强迫及其未来变化的预测需要精确了解控制二次硫酸盐气溶胶形成的SO氧化速率。鉴于放射性硫（宇宙成因硫放射性核素）的独特单一来源，已采用对二氧化硫（SO）和硫酸盐（SO）中的大气放射性硫进行联合测量来限制大气中的硫氧化速率。这种方法采用箱式模型计算，纳入了几个关键假设参数，包括硫沉积速率。然而，先前的计算没有充分考虑参数化中的不确定性，因此有必要重新审视估计值。在本研究中，我们应用一种新方法重新审视沿海和内陆站点现有的SO和SO联合测量数据。通过全面考虑参数化不确定性，我们估计了SO氧化速率的时空变化。我们采用了大气化学与气候模型相互比较项目九个模型的沉积数据。通过蒙特卡罗方法评估了沉积数据和其他关键参数（如宇宙成因硫生成速率和自由对流层中SO/SO比率）的不确定性。我们的新分析揭示了比先前估计更高的SO氧化速率，这与最近的多相动力学研究一致。此外，通过将这些结果与硫酸盐氧 - 17异常进行比较，阐明了SO氧化速率变化与硫酸盐形成途径之间的潜在关系。我们的方法和发现对各种硫酸盐形成途径如何对行星边界层中的整体SO氧化速率产生贡献提供了严格评估，因此有助于评估大气硫循环对环境健康、公众健康和气候的影响。
