中国城市空气质量的区域差异及归因分析
赵艳艳, 张晓平, 陈明星, 高珊珊, 李润奎

Regional variation of urban air quality in China and its dominant factors
ZHAO Yanyan, ZHANG Xiaoping, CHEN Mingxing, GAO Shanshan, LI Runkui
图2 2014—2019年城市6种空气污染物年均浓度
Fig. 2 Annual average concentrations of six urban ambient air pollutants from 2014 to 2019