Based on the air pollution observation data for 25 cities in the middle reaches of the Yangtze River from January 2015 to November 2016, the feature classification of urban air pollution is studied by a fuzzy clustering analysis. The quantitative analysis of the classification results shows that the results that are based on different pollutant components are significantly different, and the differences in the urban air pollution characteristic categories under the same pollutant component classification criteria are obvious. For example, the classification difference for the nine cities in Jiangxi Province between the classification results according to the characteristics of PM2.5 and truncated set level lambda = 0.885 and the characteristics of CO and the truncated set level lambda = 0.90 is 0.7143. The 25 major cities in the middle reaches. of the Yangtze River are classified according to the CO characteristics and the truncated set level lambda = 0.87. They are classified into 5 categories, namely, {Wuhan, Yichang, Shiyan, Xiangyang, Jingzhou, Huanggang, Changsha, Yueyang, Xiangtan, Zhuzhou, Henyang, Nanchang, Jiujiang, Ganzhou, Jingdezhen, Yingtan, Jian, Yichun, {Xiaogan, Xianning, Huangshi}, {Yiyang}, {Loudi} and {Shangrao}, and their category center distances and their proportions to the category extreme differences are (0.28, 37%), (0.28, 37%), (0.28, 37%), (0.28, 37%), (0.28, 37%) and (0.28, 37%), respectively. Finally, some suggestions on the classification and treatment of urban air pollution are recommended.
