Department of Physics, Lund University, Professorsgatan 1, Lund SE-22363, Sweden.
Swedish Meteorological and Hydrological Institute (SMHI), Norrköping SE-60176, Sweden.
Environ Sci Technol. 2024 Apr 30;58(17):7314-7324. doi: 10.1021/acs.est.3c09103. Epub 2024 Apr 16.
New particle formation via the ion-mediated sulfuric acid and ammonia molecular clustering mechanism remains the most widely observed and experimentally verified pathway. Recent laboratory and molecular level observations indicate iodine-driven nucleation as a potentially important source of new particles, especially in coastal areas. In this study, we assess the role of iodine species in particle formation using the best available molecular thermochemistry data and coupled to a detailed 1-d column model which is run along air mass trajectories over the Southern Ocean and the coast of Antarctica. In the air masses traversing the open ocean, ion-mediated SA-NH clustering appears insufficient to explain the observed particle size distribution, wherein the simulated Aitken mode is lacking. Including the iodine-assisted particle formation improves the modeled Aitken mode representation with an increase in the number of freshly formed particles. This implies that more particles survive and grow to Aitken mode sizes via condensation of gaseous precursors and heterogeneous reactions. Under certain meteorological conditions, iodine-assisted particle formation can increase cloud condensation nuclei concentrations by 20%-100%.
通过离子介导的硫酸和氨分子簇机制形成新粒子仍然是最广泛观察到和经过实验验证的途径。最近的实验室和分子水平的观测表明，碘驱动成核是新粒子形成的一个潜在重要来源，特别是在沿海地区。在这项研究中，我们使用最好的可用分子热化学数据来评估碘物种在颗粒形成中的作用，并将其与详细的 1 维柱模型耦合，该模型沿着大气质量轨迹在南大洋和南极洲海岸上空运行。在穿越开阔海洋的气团中，离子介导的 SA-NH 聚类似乎不足以解释观测到的颗粒尺寸分布，其中模拟的艾肯模式缺失。通过包括碘辅助的颗粒形成，可以通过气态前体的冷凝和多相反应增加新形成的颗粒数量，从而改善模拟的艾肯模式表示。这意味着更多的颗粒通过气态前体的冷凝和多相反应幸存并生长到艾肯模式尺寸。在某些气象条件下，碘辅助的颗粒形成可以使云凝结核浓度增加 20%到 100%。
