Modifications of the physicochemical properties and oxidative potential (OP) of soot due to visible-light irradiation and its underlying mechanisms during atmospheric aging have not been elucidated. In this study, two types of soot obtained using different air/fuel ratios (A/F) were aged under visible light with or without ozone (O₃) at an atmospherically relevant level in an environmental chamber. Physicochemical characteristics and OP of aged soot were systematically measured using the dithiothreitol (DTT) assay (OP^DTT). Regardless of the presence of O₃, visible light markedly promoted oxidation of soot, which led to consumption of polycyclic aromatic hydrocarbons, formation of oxygen-containing functional groups, and enhancement of OP^DTT values. Compared to low-A/F soot, high-A/F soot contained more elemental carbon but less organic carbon and was more sensitive to visible light by exhibiting greater changes. It was proposed that elemental carbon in soot under visible-light irradiation initiated an inside-to-outside oxidation pathway, where reactive oxygen species played an important role. This study clarified the solar irradiation-triggered self-oxidation process in soot, which is important to its atmospheric and health effects.

中文翻译：

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活性氧与可见光辐照触发的烟尘颗粒的由内而外的氧化：理化性质的变化和氧化电位的增强。

还没有阐明由于烟灰在大气老化过程中由于可见光照射而引起的物理化学性质和氧化电位（OP）的变化及其潜在机理。在这项研究中，将使用不同空燃比（A / F）获得的两种烟灰在有或没有臭氧（O ₃）的可见光下在环境室内与大气相关的水平下老化。使用二硫苏糖醇（DTT）测定法（OP ^DTT）系统地测量了老化烟灰的理化特性和OP 。无论O ₃的存在如何，可见光均会显着促进烟灰的氧化，从而导致多环芳烃的消耗，含氧官能团的形成以及OP ^DTT的增强价值观。与低A / F烟灰相比，高A / F烟灰包含更多的元素碳，但有机碳更少，并且通过显示更大的变化对可见光更敏感。有人提出，可见光照射下烟灰中的元素碳引发了由内而外的氧化途径，其中活性氧起着重要的作用。这项研究阐明了太阳辐射触发烟灰中的自氧化过程，这对其烟尘和健康影响至关重要。