Organic-lean and organic-rich size-selected soot particles were exposed to a varying O₃ concentration, progressively decreasing the soot-water contact angle (θ) to study its impact on ice nucleation (IN). The IN ability of fresh and O₃-aged soot between 218 and 233 K was observed while monitoring the particle mass and size distributions. The properties of fresh and O₃-aged bulk organic-lean soot samples with a low and high O₃-adsorption were characterized for soot-water θ, chemical composition, functional groups, soot-water interaction ability and porosity. By retaining the soot porosity between aged and unaged samples, we demonstrate that a decrease in θ after O₃-aging enhances organic-lean soot IN via pore condensation and freezing. Fresh organic-rich soot exhibits suppressed homogeneous freezing, but after O₃-aging it freezes within uncertainty of the homogeneous freezing threshold of solution drops, because of increased hydrophilicity.

中文翻译：

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降低烟灰-水接触角对臭氧老化烟灰冰核的影响

将贫有机物和富含有机物尺寸选择的烟灰颗粒暴露于不同的 O ₃浓度，逐渐减小烟灰-水接触角 ( θ )，以研究其对冰成核 (IN) 的影响。在监测颗粒质量和尺寸分布的同时，观察了新鲜烟灰和 O ₃老化烟灰在 218 至 233 K 之间的 IN 能力。具有低和高O _{3吸附的新鲜和O 3}陈化的散装贫有机烟灰样品的特性被表征为烟灰-水θ、化学成分、官能团、烟灰-水相互作用能力和孔隙率。通过保留老化和未老化样品之间的烟灰孔隙率，我们证明O _3老化后θ的减小通过孔隙冷凝和冷冻增强了贫有机烟灰IN。新鲜的富含有机物的烟灰表现出抑制的均匀冻结，但在O ₃老化后，由于亲水性增加，它在溶液滴的均匀冻结阈值的不确定范围内冻结。