Located in the hinterland of the North China Plain,Beijing,Tianjin and Hebei are facing serious air pollution,especially the key industrial city of Tangshan in Hebei,which has long been in the top ten of the worst air quality cities.To improve air quality,China has continuously enacted and implemented several pollution prevention and control programs over the past decade,but PM_2.5 and summer O₃ levels in Tangshan still exceed the national standards.This study quantifies the sectoral contributions to PM_2.5 and O₃ in Tangshan in 2020 using the WRF-CMAQ model and analyzes the feasibility of the synergistic control.Industrial sources contribute the most to PM_2.5 in Tangshan,accounting for about 45％,followed by residential sources with contributions of 16％.In winter,energy,residential sources and agricultural sources account for 17％,19％ and 11％,respectively.Background values of O₃ account for about more than half,with the highest percentage in April.Among the non-background values,the largest source of O₃ in Tangshan is industrial sources,accounting for about 53％,followed by traffic sources with contributions of 22％.The contributions from biological sources,traffic sources and energy sector increased in July,with values of 10％,27％ and 20％,respectively.Comparison of the sources of PM_2.5 and O₃ in Tangshan under different pollution scenarios reveals that industry and energy are the most important common sources.