Tropospheric reactive bromine is important for atmospheric chemistry, regional air pollution, and global climate. Previous studies have reported measurements of atmospheric reactive bromine species in different environments, and proposed their main sources, e.g. sea-salt aerosol (SSA), oceanic biogenic activity, polar snow/ice, and volcanoes. Typhoons and other strong cyclonic activities (e.g. hurricanes) induce abrupt changes in different earth system processes, causing widespread destructive effects. However, the role of typhoons in regulating reactive bromine abundance and sources remains unexplored. Here, we report field observations of bromine oxide (BrO), a critical indicator of reactive bromine, on the Huaniao Island (HNI) in the East China Sea in July 2018. We observed high levels of BrO below 500 m with a daytime average of 9.7 ± 4.2 pptv and a peak value of ∼26 pptv under the influence of a typhoon. Our field measurements, supported by model simulations, suggest that the typhoon-induced drastic increase in wind speed amplifies the emission of SSA, significantly enhancing the activation of reactive bromine from SSA debromination. We also detected enhanced BrO mixing ratios under high NOx conditions (ppbv level) suggesting a potential pollution-induced mechanism of bromine release from SSA. Such elevated levels of atmospheric bromine noticeably increase ozone destruction by as much as ∼40% across the East China Sea. Considering the high frequency of cyclonic activity in the northern hemisphere, reactive bromine chemistry is expected to play a more important role than previously thought in affecting coastal air quality and atmospheric oxidation capacity. We suggest that models need to consider the hitherto overlooked typhoon- and pollution-mediated increase in reactive bromine levels when assessing the synergic effects of cyclonic activity on the earth system.

中文翻译：

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台风和污染驱动的中纬度海洋边界层活性溴增强

对流层活性溴对于大气化学、区域空气污染和全球气候很重要。先前的研究报道了不同环境中大气活性溴物种的测量，并提出了它们的主要来源，例如海盐气溶胶（SSA）、海洋生物活动、极地雪/冰和火山。台风和其他强烈气旋活动（例如飓风）会引起不同地球系统过程的突然变化，造成广泛的破坏性影响。然而，台风在调节活性溴丰度和来源方面的作用仍有待探索。在此，我们报告了 2018 年 7 月在东海花鸟岛 (HNI) 对氧化溴 (BrO) 的现场观测，氧化溴是活性溴的关键指标。我们观察到 500 m 以下的高浓度 BrO，白天平均值为9.7 ± 4.2 pptv，台风影响下峰值约为 26 pptv。我们的现场测量在模型模拟的支持下表明，台风引起的风速急剧增加放大了SSA的排放，显着增强了SSA脱溴反应中活性溴的活化。我们还在高 NOx 条件（ppbv 水平）下检测到 BrO 混合比增强，这表明 SSA 释放溴的潜在污染诱导机制。大气中溴含量的升高使东海的臭氧破坏显着增加了约 40%。考虑到北半球气旋活动的频繁程度，预计活性溴化学在影响沿海空气质量和大气氧化能力方面将发挥比之前想象的更重要的作用。我们建议，在评估气旋活动对地球系统的协同效应时，模型需要考虑迄今为止被忽视的台风和污染引起的活性溴水平增加。