Pollution Characteristics and Sensitivity Analysis of Atmospheric Ozone in Taian City

Abstract

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 (NOx) 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/NOx, and H2O2/NOz) and the empirical kinetics modeling approach (EKMA) curve method that the photochemical generation of O3 in Taian was controlled by the NOx concentration and the transition area, which means that reducing the emissions of NOx 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 NOx according to a PE:NOx concentration ratio of 8:3.