Characteristics of Ozone Pollution and Relationships with Meteorological Factors in Jiangxi Province

Abstract

Based on the pollutant data provided by the environmental monitoring stations and the routine observation data of 11 national meteorological stations in Jiangxi Province from 2016 to 2019, the characteristics of ozone pollution and the relationships with meteorological factors were investigated in this study. The results showed that ozone pollution has become increasingly severe in Jiangxi Province in recent years. The annual mean concentration of ozone in Jiangxi Province (the maximum daily 8 h average) was 80.1 μg·m-3 in 2016 and reached up to 98.2 μg·m-3 in 2019, with an average annual growth rate of 6 μg·m-3. The number of over-standard days of ozone was 475 d, accounting for 72.6% of 2019 in Jiangxi Province. The average concentrations observed in summer were higher than those observed in the other seasons during 2016 to 2018, but in 2019, higher ozone concentrations were observed in autumn owing to the lower precipitation, more sufficient sunshine, and the resulting higher air temperature. Overall, the ozone concentrations were found to be positively correlated with air temperature and sunshine but negatively correlated with relative humidity in Jiangxi Province. A high ozone concentration usually appeared with an air temperature higher than 30℃, relative humidity of 20%-40%, and wind speed of 2-3 m·s-1. The spatial distribution of the ozone concentrations exhibited distinct characteristics with higher values observed in southern Jiangxi relative to those in the northern areas and lower values in northeastern Jiangxi compared with those in other regions. More serious ozone pollution was found in Ganzhou among the 11 cities in Jiangxi Province, with the highest annual concentration of 104.2 μg·m-3 observed in 2019. The results of the model analyses, including the HYSPLIT backward trajectory model and potential source contribution function model, indicated that there was a significant difference in the potential source contribution of ozone pollution in Ganzhou on seasonal scales, specifically in central Guangdong and the northwest of Jiangxi Province in spring, the northwest parts of Jiangxi Province in summer, and the north of Guangdong and central Anhui Province in autumn.