Sulfate aerosol is a major fraction of haze, playing an important role in aerosol formation and aging processes. To understand the mechanism of sulfate formations, the characteristics of sulfur isotope composition were determined during different heterogeneous oxidation reactions of sulfur dioxide on the surface of α-Fe₂O₃. Although NH₃ was more beneficial to the formation of sulfate, compared with NO_X and O₃, ³⁴S tended to enrich the lighter sulfur isotopes in the presence of NH₃. Furthermore, in consideration of the potential competitive effects of NO_X, O₃, and NH₃ in the heterogeneous oxidation processes, the contributions of each gas were evaluated via Rayleigh distillation model. Notably, the oxidation by NO_X contributed 67.5±10 % of the whole sulfate production, which is higher than that of O₃ (13.3±10 %) and NH₃ (19.2±10 %) on the basic of the average fractionation factor. The observed δ³⁴S values of sulfate aerosols were negatively correlated with sulfur oxidation ratios, owing to the sulfur isotopic fractionations during the sulfate formation processes. Given the isotope mass balance, the overall δ³⁴S_sulfate approached the δ³⁴S_emission as oxidation of SO₂ progressed, suggesting that NO_X played a major rather than a sole role in the different heterogeneous oxidation processes of SO₂ on the mineral dust surface.

硫酸盐气溶胶是雾霾的主要组成部分，在气溶胶形成和老化过程中发挥着重要作用。_{为了了解硫酸盐形成的机理，测定了二氧化硫在α-Fe 2} O ₃表面的不同非均相氧化反应过程中硫同位素组成的特征。尽管NH ₃更有利于硫酸盐的形成，但与NO _X和O ₃相比，^{34 S在NH} ₃存在下倾向于富集较轻的硫同位素。此外，考虑到NO _X、O ₃和NH ₃在非均相氧化过程中潜在的竞争效应，通过瑞利蒸馏模型评估了每种气体的贡献。_{值得注意的是，NO X}氧化占硫酸盐总产量的67.5±10%，从平均分馏因子来看，高于O ₃ (13.3±10%)和NH _{3 (19.2±10%)。}由于硫酸盐形成过程中的硫同位素分馏，观察到的硫酸盐气溶胶的 δ ^{34 S 值与硫氧化率呈负相关。}考虑到同位素质量平衡，随着SO _{2氧化的进行，总体δ} ³⁴ S_硫酸盐接近δ ³⁴ S_排放，这表明NO _X在矿尘上SO ₂的不同非均相氧化过程中发挥了主要作用，而不是唯一作用。表面。