中文摘要：

利用2012年杭州地区（杭州、桐庐、建德、淳安）大气颗粒物监测仪TEOM1405D的连续观测资料，对该地区PM2．5质量浓度的变化特征及其与气象条件的关系进行了分析研究．结果表明，2012年杭州、桐庐、建德、淳安PM2．5年平均浓度分别为50．0±25．7、46．5±22．0、42．1±21．8、36．9±21．2μg·m^－3，空间上呈现至北向南逐渐下降的变化趋势．受边界层高度、降水等气象条件影响，4个站点PM2．5浓度的季节变化基本表现为秋季＞冬季＞春季＞夏季，其中秋、冬季PM2．5超标日数高达80％左右．杭州地区PM2．5日变化呈现明显的双峰型特征，其峰值出现时间与人们的早晚出行高峰有较好的对应关系．对比不同站点PM2．5浓度变化可以看出人口密集城市区域气溶胶浓度要显著高于乡村地区．通过拟合小时平均值最大出现频率得出杭州地区最具代表性大气状态下PM2．5的浓度值为21．2μg·m^－3．风向风速与PM2．5浓度的关系表明杭州主要以本地污染为主，桐庐受本地污染和区域输送双重影响，建德主要表现为区域输送．

英文摘要：

The characteristics of PM2.5 mass concentrations and its relationship with meteorology were analyzed by continuous observation collected by the atmospheric particulate monitor TEOM1405D in 2012 in Hangzhou region （ Hangzhou, Tonglu, Jiande, Chun′an） . The results show that the annual mean concentrations of PM2.5 in Hangzhou, Tonglu, Jiande, Chun′an were 50.0±25.7,46.5±22.0, 42.1±21.8,36.9±21.2 μg·m^-3, respectively, presenting a trend of gradual decrease from north to south. Due to the height of planetary boundary layer, precipitation and other meteorological conditions, the seasonal variation of PM2.5 concentrations was autumn 〉 winter 〉 spring 〉 summer. The number of days for PM2.5 concentration over the standard was as high as 80% in autumn and winter. The significant diurnal variation of PM2.5 displayed a bimodal pattern. The peaks of PM2.5 usually appeared in the morning and evening rush hours. Comparing the concentrations at PM2.5 of different sites, the aerosols in the urban area are obviously higher than in the rural area. The concentration of PM2.5 under the most representative air condition of Hangzhou was 21.2 μg·m-3, which was calculated by fitting hours frequency distribution. Correlation analysis based on wind direction and wind speed related to PM2.5 concentrations shows the influence of transfer and diffusion of PM2.5 in different sites. Hangzhou was polluted dominantly by local pollutions, and Tonglu was under dual influence of local pollution and regional transfer, while Jiande was mainly affected by regional transfer.