Shen Hengqing, Li Qinyi, Xu Fei, Xue Likun, Hu Yongxia, Saiz-Lopez Alfonso, Wang Wenxing, Wang Tao
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
Environment Research Institute, Shandong University, Qingdao, China.
Nat Commun. 2025 Sep 1;16(1):8148. doi: 10.1038/s41467-025-63420-3.
Reactive nitrogen plays critical roles in atmospheric chemistry, climate, and geochemical cycles, yet its sources in the marine atmosphere, particularly the cause of the puzzling daytime peaks of nitrous acid (HONO), remain unexplained. Here we reveal that iodide enhances HONO production during aqueous nitrate photolysis by over tenfold under typical marine conditions. Laboratory experiments and molecular simulations confirm that HONO formation from nitrate photolysis is a surface-dependent process, and the extreme surface propensity of iodide facilitates nitrate enrichment at interfaces, reducing the solvent cage effect and promoting HONO release. Global model simulations show that this process accelerates atmospheric nitrogen cycling, increasing the levels of nitrogen oxides, hydroxyl radicals, and ozone by over 25%, 30%, and 15%, respectively, and enhancing dimethyl sulfide and methane degradation by over 20% in the marine boundary layers. Our findings highlight the crucial role of iodide in interfacial photochemistry and marine atmospheric nitrogen cycling.
活性氮在大气化学、气候和地球化学循环中起着关键作用，但其在海洋大气中的来源，尤其是令人费解的亚硝酸（HONO）白天峰值的成因，仍未得到解释。在此，我们揭示了在典型的海洋条件下，碘化物可使硝酸盐光解过程中HONO的生成增强十倍以上。实验室实验和分子模拟证实，硝酸盐光解生成HONO是一个表面依赖过程，碘化物的极端表面倾向促进了硝酸盐在界面处的富集，减少了溶剂笼效应并促进了HONO的释放。全球模型模拟表明，这一过程加速了大气氮循环，使海洋边界层中的氮氧化物、羟基自由基和臭氧水平分别增加了25%以上、30%以上和15%以上，并使二甲基硫和甲烷的降解增强了20%以上。我们的研究结果突出了碘化物在界面光化学和海洋大气氮循环中的关键作用。
