Trends of urban haze in Jiangsu Province China over the past 33 years

Based on the surface meteorological data of Jiangsu Province during 1980-2012,climatic characteristics and trends of the weather phenomenon of haze were analyzed. The result indicates that during 1980-2012,the haze day increased,and the severe and moderate haze days significantly increased. In the northern and coastal cities,haze days had a significant increase. Haze is often appeared in the fall and winter,and is rare in the summer,it also occurs inland,and is less in the coast. The haze happens more frequently in June since the straw burning during summer harvest time. The haze day was evenly distributed during the 80's,and increased during the 90's over southern and southwestern Jiangsu Province,middle and northern Jiangsu haze days had a growing after2000,especially after 2010. The continuous,regional,and regional-continuous haze days were in an increasing trend. As the urban built-up area has been expanded each year,industrial emissions,coal consumption,and car ownership increase every year,resulting in regional temperature increase and relative humidity decrease,resulting in urban heat island and dry island effects. Thence the haze formation and maintenance conditions increased,which led to the increasing of haze days,and the continuous,regional and regionalcontinuous haze days were significantly increased.