[Pollution Characteristics and Sensitivity Analysis of Atmospheric Ozone in Taian City]

Online monitoring of ozone (O₃) and its precursors was carried out at urban stations in Taian City from May to July, 2018. The pollution characteristics of O₃ and its precursors and the sensitivity of O₃ generation to its precursors were also analyzed based on the characteristic ratio method and a photochemical model. The results indicated that Taian City was suffering from serious O₃ pollution during the observation period. The daily variation of the O₃ concentration exhibited an obvious convex trend with the highest value at approximately 15:00, whereas the concentrations of nitrogen oxide (NO) and VOCs had decreasing trends during the daytime and increasing trends during the night. It was concluded from the results of the characteristic ratio methods (OPE, VOCs/NO, and H₂O₂/NO) and the empirical kinetics modeling approach (EKMA) curve method that the photochemical generation of O₃ in Taian was controlled by the NO concentration and the transition area, which means that reducing the emissions of NO and VOCs has a controlling effect on O₃ pollution. Additionally, the results of the EKMA curve method also showed that the best effect of O₃ concentration control could be achieved by reducing the concentration of O₃ precursors, and reducing the concentrations of VOCs (propylene equivalent, PE) and NO according to a PE:NO concentration ratio of 8:3.