资源环境科技发展态势分析平台

Sulfate as the major constituent of atmospheric aerosol plays a key role in aerosol formation and aging processes. However, little attention has been paid to the impacts of mineral dust on the oxidation of SO₂, along with the effects of temperature, moisture, and light intensity. In this study, the influences of these parameters on the formation of sulfate and sulfur isotope composition were investigated in detail. Temperature promoted the heterogeneous oxidation of SO₂ on the surface of hematite (α-Fe₂O₃), while excessive temperature was unfavorable for sulfate formation. Besides, the effect of temperature on sulfur isotope fractionation was not apparent. In addition, relative humidity (RH, < 40%) boosted the oxidation of SO₂ with the concurrent enrichment of heavy isotope. Meanwhile, light with high intensity inhibited the formation of sulfate due to the photo-induced reductive dissolution of hematite, and had little effects on the sulfur isotope compositions. Furthermore, compared with other minerals, α-Fe₂O₃ exhibited greater uptake capacity of SO₂, favoring the enrichment of light sulfur isotopes, whereas the enrichment of heavy sulfur isotopes existed on the surface of MgO. This study contributes to the investigation of the heterogeneous oxidation of SO₂ and provides useful parameters for atmospheric modeling studies.