[Spatiotemporal Variation Characteristics of Ozone and Identification of Key Influencing Factors Based on Random Forest Model： A Case Study of Chuzhou City].

Abstract

The cause of ozone pollution is a complex scientific problem. Studying the spatiotemporal variation characteristics of O₃ at different time scales and analyzing the key influencing factors of O₃ concentration is of great significance for the precise formulation of urban air pollution control measures and the improvement of urban air quality. Based on the analysis of the spatiotemporal variation characteristics of O₃ concentration in Chuzhou City, we studied the 12 ozone-influencing factors of meteorology and pollutants at multiple time scales using Spearman correlation analysis and a random forest model. The results showed that： ① The O₃ pollution level of Chuzhou City showed an aggravating trend, and the O₃ concentration distribution showed a spatial pattern of "high in the southeast and low in the northwest." ② From February to May, SO₂ concentration had a strong impact on the increase in O₃ concentration. From June to September, PM_2.5 and PM₁₀ were significantly positively correlated with ozone and had a greater impact. ③ Relative humidity, temperature, and wind speed had a significant impact on O₃, whereas barometric pressure and hourly rainfall had a weak impact. ④ The O₃ pollution mechanism in Chuzhou City changed from "pollutant-controlled" to "meteorology-controlled." ⑤ Among meteorological and pollutant factors, the three influencing factors that had the greatest influence on O₃ concentration were temperature, wind speed, and relative humidity, with PM₁₀ concentration, PM_2.5 concentration, and SO₂ concentration also contributing. All of the above six influencing factors had a significant nonlinear relationship with the O₃ concentration.