Abstract: Based on the hourly ozone (O3) concentration monitoring data of the national control points in Nantong City from 2017 to 2020 and the hourly meteorological data of the national basic meteorological station in Nantong City, China, during the same period, the interannual variation, monthly variation, daily variation of ozone pollution changes in Nantong City were analyzed, as well as the relationship between O3 pollution characteristics and meteorological factors. The results show that: (1) The seasonal variation amplitude of ozone concentration is summer > spring > autumn > winter, and diurnal variation of O3 shows a unimodal trend, with the lowest value usually occuring during 06: 00 – 07: 00 am and the highest value around 15:00. (2) The O3 concentration is positively correlated with temperature, and negatively correlated with relative humidity. When the temperature is greater than 20 °C, the relative humidity is between 30% and 50 %, and the wind speed is between 0 m/s and 4 m/s, the O3 concentration is often high, and excessive conditions are likely to occur.

Key words: ozone characteristics, meteorological factors, Nantong City