长江经济带三大城市群PM_(2.5)时空分布特征及影响因素研究

Spatiotemporal Distribution Characteristics of PM_(2.5) and Its Influencing Factors of the Three Urban Agglomerations in the Yangtze River Economic Belt

基于国控点发布的2017~2019年PM_(2.5)数据,综合运用空间自相关分析法、地理探测器和混合地理加权回归(MGWR)等方法,对长江经济带三大城市群PM_(2.5)浓度进行多空间尺度、多影响指标和多分析模型的综合研究。结果表明:(1)长江经济带三大城市群的PM_(2.5)浓度总体上呈下降趋势,长江三角洲城市群三年平均PM_(2.5)浓度值最低,长江中游城市群三年平均PM_(2.5)浓度最高,但下降幅度最大,成渝城市群三年内空气质量在三大城市群中处于中等水平。(2)在季节尺度上,春冬季PM_(2.5)浓度值较高,夏秋季较低。(3)空间视角,长江以北空气污染较长江以南更为严重,长江三角洲城市群东部和南部的空气质量优于该城市群的其他地区,长江中游城市群西北部空气质量较差,成渝城市群东部空气质量较好。(4)PM_(2.5)浓度的影响因素主要包括气象因素和社会经济因素。社会经济因素中,城镇化率是2017~2019年PM_(2.5)污染的最主要影响因子,其次为规模以上工业企业。气象因素中,总降水量、最高气温等因素对PM_(2.5)污染有较强的削弱作用。总体上,现阶段城市化进程对PM_(2.5)污染的影响程度较大。

The present study used spatial autocorrelation analysis,geo-detector and mixed geographically weighted regression(MGWR) methods to analyze the 2017-2019 PM_(2.5) data of three urban agglomerations along the Yangtze River Economic Belt under the National Monitoring System and established multiple spatial scales,multiple impact indicators and multiple analysis models for a comprehensive assessment of the PM_(2.5) concentrations.The results showed that:(1) The PM_(2.5) concentration in the three urban agglomerations had a generally downward trend over the three years.The average PM_(2.5) concentration in the Yangtze River Delta urban agglomeration was the lowest for the three years under the study,and the average PM_(2.5) concentration in the Yangtze River Middle-Reach urban agglomeration was the highest for the three years,but the decline was the largest.The air quality in the Cheng-Yu urban agglomeration was overall between the levels of the two aforementioned agglomerations.(2) On the seasonal scale,PM_(2.5) concentration was higher in the spring and winter,but lower in summer and autumn.(3) From the spatial perspective,air pollution in the north of the Yangtze River was more severe than that in the south of the Yangtze River.The air quality in the eastern and southern parts of the Yangtze River Delta urban agglomeration was better than that in other regions of the same agglomeration.The air quality in the northwest part was worse than other regions of the Yangtze River Middle-Reach urban agglomeration,and for the Cheng-Yu urban agglomeration,the air quality in the eastern part was better.(4) Meteorological elements and socio-economic status were the main factors affecting the PM_(2.5) concentration.Among social and economic factors,the urbanization rate was found to be most impactful for PM_(2.5) pollution from 2017 to 2019,followed by industrial enterprises above designated size.Among meteorological factors,total precipitation,maximum temperature and other factors showed a strong weakening effect on PM_(2.5) pollution.In general,the current urbanization process had a greater impact on PM_(2.5) pollution.