长江三角洲地区四省会城市PM10污染特征

Characteristics of PM_(10) Pollution at Four Provincial Cities in Yangtze River Delta District

对长江三角洲地区四省会城市(上海、南京、杭州、合肥)2001-2005年逐日大气污染指数资料进行统计分析,并采用HYSPLIT轨迹模式,分析了各城市中度以上大气污染过程的输送特征。结果表明:2002年以后,四省会城市的大气质量都有好转的趋势;大气污染发生频率最高的季节是春季(南京)和冬季(其他城市);11月和3月是大气污染出现频率最高的月份。上海PM10与NO2和SO2浓度之间存在非常显著的正相关,合肥PM10与NO2和SO2浓度之间的相关性比上海略差。两城市都是PM10与NO2之间的偏相关系数远大于与SO2之间的偏相关系数。各城市的PM10浓度都与另外三个城市之间存在显著的正相关,尤其是3,4月份。后向轨迹分析表明,造成本地区中度以上大气污染的气团以西北来向为主。

Statistic analyses were done based on the daily concentration/index data at four provincial capital cities in Yangtze River delta of East China from January 2001 to December 2005.Trajectory model（HYSPLIT4） was used to analysis the back-trajectories on medium and heavy air pollution days.The air quality turned better in all the four cities from 2002 to 2005.The seasons with the highest air pollution event were in spring and winter.The months with the highest air pollution event were in March and November.The PM10 concentration was highly correlated with those of SO2 and NO2 in Shanghai.The correlations between PM10 and SO2,NO2 in Hefei were not as good as those in Shanghai.The partial correlation between PM10 and NO2 was higher than that between PM10 and SO2 in both Shanghai and Hefei.The PM10 concentration variations in four cities were highly consistent,especially in March and April.The back-trajectory analysis indicated that the air masses leading to medium to heavy polluted events were mainly from north-west China.