Abstract: The characteristics and meteorological causes of ozone (O3) pollution in Xuancheng City, China, were analyzed based on the ambient air quality monitoring data in 2020 and the meteorological observation data of the same period. The results indicated that the 90th percentile of the maximum daily sliding 8-hour average mass concentration of O3 (MDA8-90) in 2020 was 137 μg/m3, with an increase of 2.2% compared to 2019. The monthly variation of MDA8-90 showed an "M" type, with the peak appearing in September (164 μg/m3). The diurnal variation showed a unimodal pattern, with the peak at 16:00 and the trough at 07: 00. Under different weather conditions, the peak value of O3 mass concentration was the highest on sunny days, and decreased sequentially on cloudy, overcast sky and rainy days. O3 mass concentration revealed a positive correlation with temperature and a significant negative correlation with relative humidity and NO2 concentration. Specifically, meteorological conditions with air temperatures > 25 ℃, relative humidity < 50%, and a wind speed < 2 m/s were closely related to high concentrations of O3. In addition, the potential source contribution function model (PSCF) was used to analyze the impact of pollution transport on the O3 mass concentration in Xuancheng and the distribution characteristics of potential transport sources. The results showed that the potential sources of O3 at different stages were significantly different in various periods of the year. The main potential sources of O3 from June to August were distributed in the East China Sea and the northern part of Zhejiang Province, while the main potential sources of O3 from September to November were distributed at the junction of Jiangsu, Anhui, Henan and Shandong, as well as the junction of Jiangxi and Hubei Province.

Key words: Xuancheng City, ozone, variation characteristic, meteorological factors, potential source analysis function