Fig. 1. Distribution of environmental monitoring stations and meteorological stations in Nantong City

Fig. 2. The daily maximum 8-hour average concentration of ozone concentration in Nantong City.(a) 2017; (b) 2018; (c) 2019; (b) 2020

Fig. 3. Monthly variation characteristics of O₃ mass concentration in Nantong City

Fig. 4. Daily variation characteristics of O₃ mass concentration in Nantong City

Fig. 5. Daily variation characteristics of NO₂ mass concentration in Nantong City

Fig. 6. Characteristics of annual mean variation of O₃ mass concentration and NO₂ mass concentration in Nantong City (Solid line: NO₂ mass concentration; Dashed line: O₃ mass concentration)

Fig. 7. Relationship between temperature and O₃ mass concentration. (a) Langshan Street; (b) Hongqiao

Fig. 8. Changes of O₃ mass concentration and excess rate in different temperature ranges

Fig. 9. Relationship between relative humidity and O₃ mass concentration. (a) Langshan Street; (b) Hongqiao

Fig. 10. Changes of O₃ mass concentration and excess rate in different humidity intervals

Fig. 11. Relationship between wind speed and O₃ mass concentration. (a) Langshan Street; (b) Hongqiao

Fig. 12. Variation of O₃ mass concentration corresponding with surface wind direction and wind speed