张思¹， 王格慧²

1.西安建筑科技大学 环境与市政工程学院， 西安 710055； 2.华东师范大学 地理科学学院， 上海 200241

引用格式：

张思， 王格慧. 低二氧化硫排放量条件下硫酸盐气溶胶快速形成的多相机制［J］. 中国粉体技术， 2027， 33（2）： 223-234.

Zhang Si， Wang Gehui. Multiphase mechanisms of formation of rapid sulfate aerosol under low-SO₂ emission conditions［J］. China Powder Science and Technology， 2027， 33（2）： 223-234.

DOI：10.13732/j.issn.1008-5548.2027.02.016

收稿日期： 2026-07-15， 修回日期： 2026-08-17， 上线日期： 2026-09-11。

基金项目： 国家自然科学基金项目，编号： 42407137。

第一作者： 张思（1993—），女， 副教授， 博士， 研究方向为大气二次气溶胶形成和老化机制。E-mail：szhang@xauat.edu.cn。

通信作者： 王格慧（1968—），男， 教授， 博士， 国家杰出青年科学基金获得者，研究方向为大气环境化学。E-mail：ghwang@geo.ecnu.edu.cn。

摘要： 【目的】 为了揭示我国SO₂减排与硫酸盐浓度变化之间的非线性响应关系，解析低SO₂排放量条件下硫酸盐快速生成的关键途径及其驱动机制，为PM_2.5-O₃协同控制提供理论依据。 【研究现状】 综述硫酸盐的形成路径和机制分歧，低SO₂排放量条件下PM_2.5颗粒中硝酸盐和铵盐的占比上升，改变颗粒pH、离子强度和界面离子分布，影响反应物的气粒分配、传质和反应速率，加快某些多相过程并部分抵消SO₂下降的影响；概括NO₂界面氧化SO₂反应途径和O₃液相氧化SO₂反应途径，指出NO₂界面氧化在弱酸、高NH₃及界面阴离子富集等条件下可显著加快，并通过形成HONO及随后光解生成OH·自由基，进而促进SO₂气相氧化；O₃液相氧化则在高离子强度的海盐颗粒和碱性矿尘颗粒上更易发生；由于传统大气化学数值模式主要采用稀溶液体相实验获得的动力学参数，未充分考虑真实气溶胶中的高离子强度和界面性质等因素，可能低估硫酸盐生成效率，导致对主导路径的判断不准确。 【结论与展望】 未来应通过真实颗粒模拟实验结合外场强化观测，定量区分SO₂浓度下降与化学转化效率变化对硫酸盐浓度的贡献。模式研究须考虑离子强度和界面效应等，厘清不同霾污染阶段硫酸盐生成路径转换条件和多污染物减排响应关系，为低SO₂排放量条件下PM_2.5和O₃协同治理提供科学依据。

关键词： 硫酸盐气溶胶； NO₂界面氧化路径； O₃液相氧化路径； 大气氧化性

Abstract

Significance China’s sustained clean-air actions have sharply reduced sulfur dioxide （SO₂） emissions， yet sulfate aerosol concentrations have declined much more slowly. From 2007 to 2017， SO₂ fell by 89.1%， whereas sulfate decreased by only 58.9%.This decoupling indicates that sulfate abundance is governed not only by precursor emissions but also by evolving multiphase chemistry. As fine-particle composition shifts toward nitrate-， ammonium-， and organic-rich mixtures， changes in aerosol pH， liquid water content， ionic strength， and interfacial structure can enhance SO₂ uptake and oxidation. This review examines how these changes sustain sulfate production under low-SO₂ conditions， with a focus on NO₂ interfacial oxidation pathway and O₃ aqueous oxidation pathway， as well as their implications for coordinated PM_2.5-O₃ control.

Progress Sulfate forms through gas-phase OH oxidation， cloud and fog chemistry， and heterogeneous or aqueous reactions involving H₂O₂， O₃， NO₂， organic peroxides， and transition metals. Recent experiments show that aerosol particles cannot be treated simply as dilute bulk solutions. Concentrated electrolytes， interfacial ion gradients， liquid water content， and organic coatings can alter gas uptake and reaction rates by orders of magnitude. For the NO₂ oxidation pathway， dissolved SO₂ is converted to HSO₃⁻ and SO₃²⁻， which are subsequently oxidized at the air-water interface， directly producing sulfate and HONO. The reaction is favored by weakly acidic to near-neutral particles， abundant NH₃， high relative humidity， sufficient liquid water， and interfacial enrichment of anions. In contrast， strong acidity， low humidity， cation-rich interfaces， and some organic coatings suppress it. Measured interfacial rate coefficients exceed traditional bulk solution values by three to four orders of magnitude. HONO photolysis also produces OH radicals， coupling sulfur， nitrogen， and radical chemistry while indirectly accelerating gas-phase SO₂ oxidation. Modeling and paired gas-particle sulfur isotope observations support the atmospheric importance of this pathway during haze. O₃ oxidation proceeds by oxygen transfer to dissolved sulfite and is strongly controlled by acidity， water content， ionic strength， and particle composition. It becomes especially efficient in fresh sea-salt droplets， where chloride and high ionic strength promote alkalinity and reaction kinetics， and on hygroscopic alkaline mineral dust， where surface basicity facilitates SO₂ hydrolysis. Therefore， no single pathway dominates universally. NO₂ oxidation is predominant in weakly acidicurban aerosols， and O₃ oxidation becomes dominant in marine or dust-influenced environments. Divergent apportionments reflect both regional variability and incomplete model treatments of interfaces and concentrated aerosol media.

Conclusions and Prospects The nonlinear response of sulfate to SO₂ abatement is a dynamic outcome of particle composition， conversion efficiency， atmospheric oxidation capacity， and pollution stage. Future studies should combine single-particle and microdroplet experiments， in situ interfacial spectroscopy， molecular simulation， field observations， and multiscale modeling. Simultaneous measurements of gaseous and particulate sulfur isotopes， HONO， radicals， oxidants， aerosol pH， liquid water， ionic strength， metals， and organics are needed to separate direct sulfate production from oxidation feedback effects and to quantify precursor decline versus enhanced conversion. Kinetic parameterizations should vary with composition， pH， humidity， phase state， and organic coatings， rather than relying on fixed dilute-solution constants. Coordinated observations across coastal sea-salt regions， cold regions of northeastern China， dust-affected areas of northwestern China， and urban clusters should identify the conditions under which dominant pathways shift. These advances will enable more reliable evaluation of coupled SO₂， NOx， NH₃， and O₃-precursor controls and support region-specific strategies for joint PM_2.5 and O₃ mitigation.

Keywords： sulfate aerosol； NO₂ interfacial oxidation pathway； O₃ aqueous oxidation pathway； atmospheric oxidation capacity

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