中文摘要：

PM2.5浓度值增加对大气能见度、人体健康和气候变化有着重要影响。采用2015年长三角地区监测数据,运用探索性空间数据分析法和相关系数法,分析长三角地区城市PM2.5污染的时空格局和影响因素,结果表明：（1）2015年长三角地区城市PM2.5年均浓度值为54.54μg/m~3,季节变化总体呈现春冬高夏秋低的季节性周期变化规律,1月和12月为一年中PM2.5污染最严重的月份,污染范围最广,5-9月是PM2.5浓度值优良时段,日均值春季和冬季的波动周期较短而剧烈,夏季和秋季波动周期相对较长而平缓。（2）2015年长三角地区城市PM2.5年均浓度值整体上从江苏到浙江呈减少趋势,具有北高南低,局部突出的特征。（3）长三角地区城市PM2.5浓度空间上存在集聚现象,低值集聚主要分布在浙江沿海地区,高值集聚主要分布在苏南地区。（4）燃烧排放的烟尘和前体物的二次转化对长三角地区PM2.5浓度有显著影响。风速和降水量是影响PM2.5浓度的两个重要气象因素。

英文摘要：

The increase of PM2.5 concentration has a vital influence on atmospheric visibility, human health and climate change. This paper adopts the monitoring data of the Yangtze River Delta in 2015, employs the analytical method of exploratory spatial data and relative coefficient method, and analyzes the spatial-temporal pattern and influencing factors of PM2.s in cities of the Yangtze River Delta. The results showed that： 1） The average annual concentration of PM2.5 in Yangtze River Delta region is 54.54μg/m3. The level is high in spring ＆ winter and low in summer ＆ autumn in general. January and December are the months of most polluted, with widest range of pollution. The concentration is low in months during May to September. The average daily value of wave period in spring and winter is shorter and intense, while in summer and autumn is longer and gentle. 2） In 2015, the average annual concentration of PM2.5 in the Yangtze River Delta region is decreasing from Jiangsu to Zhejiang, which has the characteristics of high in north and low in south, local projecting. 3） In the Yangtze River Delta region, low concentration of PM2.5 in the urban agglomeration is mainly distributed in the coastal area of Zhejiang Province, and the high value agglomeration is mainly distributed in the South of Jiangsu area. 4） The soot emitted by burning and the quadratic transformations of precursor has a significant impact on the concentration ofPM2.5 in Yangtze River Delta region. Wind speed and precipitation are the two important meteorological factors that affect the concentration of PM2.5.