Abstract:The latest ERA Interim radiosonde and surface data with high spatio temporal resolution are used to analyze the change characteristics of spatio temporal distribution of the atmospheric transport and self purification capability in Zhejiang Province. Combining with air quality data from Environmental Protection Agency, the relationship between air quality and atmospheric self purification capability in Zhejiang is explored. The results show that atmospheric self purification capability is smaller in coastal areas and larger in inland during spring and summer, but increases in coastal areas and decreases in inland when it comes to autumn and winter. The average atmospheric self purification capability is in the increasing trend during the study period. The 10 m wind speed which represents the underlying transmission is the biggest in autumn and winter, but is the smallest in summer, slightly decreasing with time. This is one of the possible causes of the aggravated air pollution in Zhejiang. The distribution of 10 m wind speed gradually reduces from east coastal areas to western mountains in general, being slightly larger in autumn and winter, northerly winds mainly. The atmospheric self purification capability is the poorest in winter over most parts of Zhejiang, and the prevailing northerly winds tend to bring the north pollutants down, so winter is the time period when air pollution is prone to occur in Zhejiang. When the wind speed is small, and the direction turns into northwest, the pollutants are brought in Zhejiang from the north, getting accumulated, then more serious pollution weather is most likely to appear. The air pollution above medium grade occurs mainly in the developed areas like Hangzhou, Ningbo, Shaoxing, and Jinhua. Comparatively, air pollution rarely happens in coastal areas, such as Zhoushan, Wenzhou, Taizhou, due to the good atmospheric transport conditions. The air pollution occurs less frequently in Lishui and Quzhou as the result of high terrain and slow development in industry and economy.