Sulfate is one of the main components of haze fine particles, and its formation mechanism remains controversial. A lack of detailed and comprehensive field data hinders the accurate evaluation of relative roles of prevailing sulfate formation pathways. Here, we analyzed the sulfate production rates using a state-of-the-art multiphase model constrained to the observed concentrations of transition metal, nitrogen dioxide, ozone, hydrogen peroxide and other important parameters in winter and summer in the North China Plain. Our results showed that aqueous transition metal ion (TMI)-catalyzed oxidation was the most important pathway followed by the surface oxidation of Mn in both winter and summer while the hydroxyl and Criegee radical oxidations contribute significantly in summer. In addition, we also modeled the published cases for the fog and cloud conditions. It is found that nitrogen dioxide oxidation is the dominant pathway for the fog in a higher pH range while hydroperoxide and ozone oxidations dominated for the cloud.

中文翻译：

---

基于综合观测的夏季和冬季二氧化硫氧化的多相化学模型分析

硫酸盐是雾霾微粒的主要成分之一，其形成机制仍有争议。缺乏详细和全面的现场数据阻碍了对主要硫酸盐形成途径的相对作用的准确评估。在这里，我们使用最先进的多相模型分析了硫酸盐生产速率，该模型受限于华北平原冬季和夏季观察到的过渡金属、二氧化氮、臭氧、过氧化氢和其他重要参数的浓度。我们的结果表明，水性过渡金属离子 (TMI) 催化氧化是最重要的途径，其次是冬季和夏季 Mn 的表面氧化，而羟基和 Criegee 自由基氧化在夏季贡献显着。此外，我们还针对雾和云条件对已发布的案例进行了建模。发现二氧化氮氧化是较高 pH 值范围内雾的主要途径，而氢过氧化物和臭氧氧化则是云的主要途径。