[Characteristics and Analysis of Typical Ozone Pollution Processes in Hebi]

In recent years， the central plains urban agglomeration has been facing air pollution problems， of which the ozone （O₃） pollution in Hebi City has been particularly prominent， for up to five months， with the most serious pollution situation occurring in June. In this study， the period from June 20-27， 2023， which had the longest O₃ duration （8d） and high O₃ hourly average concentration of 256 μg·m^-3， was selected as a typical O₃ pollution process for characterization and analysis. Various methods， such as the positive definite matrix factor decomposition （PMF） model， air pollutant source emission inventory， and ozone formation potential （OFP）， were used to resolve ozone sources. The Meteoinfo model potential source contribution factor method （PSCF） and concentration weighting trajectory （CWT） method were used to explore the regional transport of O₃. The results showed that： ① O₃ was more strongly correlated with VOCs and became significantly negatively correlated with aromatic， alkane， and halogenated hydrocarbons， followed by NO_x. ② Based on the local traceability of VOCs， the reactive species such as isoprene， m/p-xylene， ethylene， 1，2，4-trimethylbenzene， hexanal， and toluene contributed the most to the O₃ generation， and the results of the local emission inventories and PMF modelling showed that the main sources of VOCs included solvent use sources （25.7%）， process sources （23.1%）， mobile sources （20.4%）， fossil fuel stationary combustion sources （9.9%）， biomass combustion sources （8.9%）， and natural sources （12.15%）. ③ In addition， fossil fuel stationary combustion sources and mobile sources also contributed the most to NO_x emissions. ④ In response to the pollution process， man-made sources of O₃ pollution were influenced by air masses from different directions in the surrounding cities of Xinxiang， Anyang， and Zhengzhou. Natural sources were mainly influenced by a southeastern air mass dominated by Zhoukou and Chuzhou. In summary， O₃ pollution prevention and control should focus on cutting down the enterprises with high VOCs emissions such as the coal chemical industry in Baoshan Park and the fine chemical industry in Jijishan Park in Hebi， as well as electric power enterprises mainly based on Heqi and Fenghe Power Generation Limited Liability Company， and timely checking the standards for the use of machinery at construction sites and agricultural machinery， while it is crucial to strengthen the regional joint prevention and control.