Heterogeneous sulfate aerosol formation mechanisms during wintertime Chinese haze events: air quality model assessment using observations of sulfate oxygen isotopes in Beijing
Heterogeneous sulfate aerosol formation mechanisms during wintertime Chinese haze events: air quality model assessment using observations of sulfate oxygen isotopes in Beijing
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DOI：
10.5194/acp-19-6107-2019
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发表时间：
2019-05-08
影响因子：
6.3
通讯作者：
Alexander, Becky
中科院分区：
文献类型：
--
作者：
Shao, Jingyuan;Chen, Qianjie;Alexander, Becky
空气质量模型无法再现中国冬季雾霾事件期间观测到的细颗粒物（PM2.5）浓度的大小。这种差异至少部分归因于模型中硫酸盐产生速率的低偏差，这是由于模型中缺乏气溶胶上的异质硫酸盐产生。在这项研究中，我们明确实施四个异质硫酸盐形成机制到一个区域化学传输模型，除了气相和云硫酸盐生产。我们将模型结果与2014-2015年冬季的硫酸盐浓度和氧同位素Delta O-17（SO 42-）的观测结果进行了比较，后者对不同硫酸盐生产机制的相对重要性高度敏感。模型结果表明，异质硫酸盐生产气溶胶约占20%的硫酸盐生产在清洁和污染的条件下，部分减少硫酸盐浓度的建模低偏差。模型的灵敏度研究相比，三角洲O-17（SO 42-）的意见表明，非均相硫酸盐的形成主要是由过渡金属离子催化氧化的SO2。
Air quality models have not been able to reproduce the magnitude of the observed concentrations of fine particulate matter (PM2.5) during wintertime Chinese haze events. The discrepancy has been at least partly attributed to low biases in modeled sulfate production rates, due to the lack of heterogeneous sulfate production on aerosols in the models. In this study, we explicitly implement four heterogeneous sulfate formation mechanisms into a regional chemical transport model, in addition to gas-phase and incloud sulfate production. We compare the model results with observations of sulfate concentrations and oxygen isotopes, Delta O-17(SO42-), in the winter of 2014-2015, the latter of which is highly sensitive to the relative importance of different sulfate production mechanisms. Model results suggest that heterogeneous sulfate production on aerosols accounts for about 20% of sulfate production in clean and polluted conditions, partially reducing the modeled low bias in sulfate concentrations. Model sensitivity studies in comparison with the Delta O-17(SO42-) observations suggest that heterogeneous sulfate formation is dominated by transition metal ion-catalyzed oxidation of SO2.