Abstract:Three serious PM2.5 pollution events which occurred in Shanghai on 29 October, 2-3 November and 7-8 November 2017 were investigated. They can be divided into two pollution types according to atmospheric circulation as follows. The pollution event on October 29 was transport pollution which features fast transportation and short period of pollution; the other two are static stability superimposed transport pollution which features slow transportation and long duration. By analyzing the weather conditions of the three pollution events, we found that the low wind speed, stable vertical stratification and descending motion made air pollutants difficult to disperse. The cross sections of the PM2.5 concentration, 〖JP2〗surface meteo 〖JP〗rological elements and vertical circulation from Beijing to Shanghai showed that the pollution belt was distributed in a narrow strip from north to south on October 29, and the wind which was in the mid low level and the near surface layer contributed to the pollution transport in Shanghai; the two pollution events in November had longer durations and wider ranges, and the pollution transport channel of Shanghai was the near surface layer. Calculating the stable weather index and the transport intensity index of the three pollution events were also carried out to prove that the pollution on October 29 was caused by transportation and the other two were caused by the local accumulation and transportation. By using the FLEXPART model and the 〖JP2〗Regional Atmospheric Environmental Modeling System for Eastern China (RAEMS). It was found that the potential sources of the two pollution processes in November were all around Shanghai, and the sources were concentrated, with coutributions from Jiangsu, Zhejiang, and Anhui.