Distribution Characteristics and Influencing Factors of Air Pollutants in Qujing City

Based on atmospheric pollutant concentration from the environmental air automatic stations,meteorological and local socio-economic data from 2018 to 2023 in Qujing City,an industrial city in eastern Yunnan Province,this study analyzed the spatiotemporal distribution characteristics and influencing factors of major atmospheric pollutants.The results showed that the ambient air in Qujing City presented a compound pollution characteristic dominated by PM_2.5 and O₃.The concentrations of SO₂,NO₂,CO,PM₁₀ and PM_2.5 were higher in spring and winter,and lower in summer and autumn,while the concentration of O₃ was highest in spring,followed by summer,and lowest in autumn and winter.The monthly average concentrations of SO₂,NO₂,PM₁₀,and PM_2.5 showed a peak-and-valley pattern,whereas those of CO and O₃ showed a U-shaped and inverted U-shaped distribution,respectively.The hourly concentration of O₃ showed a single-peak and single-valley variation,while the hourly variations of other atmospheric pollutants showed double-peak and double-valley patterns.Analysis of influencing factors showed that there was a correlation between NO₂,PM₁₀,PM_2.5,and CO,and O₃ was related to NO₂ and CO.Among meteorological factors,particulate matter was more affected by temperature,while O₃ was more affected by temperature,humidity,and wind speed.Regarding socioeconomic factors,the proportion of tertiary industry in gross domestic product (GDP),per capita GDP,green coverage of built-up areas,and population density were the main factors that affected the spatial changes of urban ambient air quality.Green coverage rate,urbanization rate and population density had the greatest impact on other factors.