Based on online observation data in Zibo from January 1st to February 15th, 2020, this study explores the changes of PM_2.5 concentration, chemical composition, secondary inorganic aerosol generation mechanism, and sources during the COVID-19 control period compared with pre-control time in Zibo. The results showed that during the control period, the PM_2.5 mass concentration in Zibo decreased by 41%. OC and secondary inorganic ions (SO₄²⁻, NO₃⁻, and NH₄⁺) were the main components of PM_2.5, and only the proportion of NO₃⁻ declined during this period. Furthermore, a comparison of PM_2.5 pollution episodes showed that during the control period, the production rates of sulfate and secondary organic aerosols increased, and the heterogeneous reaction played a key role in the increase of SO₄²⁻ concentration. The PMF source apportionment results indicated that secondary inorganic aerosols, secondary organic aerosols, coal-combustion sources, vehicle emissions, road dust sources, and mixed sources of biomass combustion and fireworks were the main sources of PM_2.5 in Zibo. During the control period, the contribution of coal-combustion sources and secondary organic aerosols increased. In the future, Zibo needs to emphasize control over coal-combustion sources and vehicle emissions.

基于2020年1月1日至2月15日期间淄博市的在线观测数据, 对新冠肺炎疫情初期淄博市实施管控措施前后PM_2.5浓度、化学组分、二次无机气溶胶生成机制以及来源的变化特征进行探讨。结果表明, 管控期间淄博市PM_2.5质量浓度下降41%, OC和二次无机离子(SO₄²⁻, NO₃⁻和NH₄⁺)是PM_2.5的主要组分, 管控期间只有NO₃⁻的占比下降。对比PM_2.5污染过程发现, 管控期间硫酸盐和二次有机气溶胶的产率上升, 且非均相反应途径对SO₄²⁻浓度的上升起关键作用。PMF源解析结果表明, 二次无机气溶胶、二次有机气溶胶、燃煤源、机动车排放源、道路扬尘源、生物质燃烧和烟花爆竹燃放混合源是淄博市PM_2.5的主要来源, 管控期间燃煤源和二次有机气溶胶两类源的贡献占比增大。未来, 淄博市需要在燃煤源、机动车排放等方向继续加强管控。