材料期刊网

利用嘉兴2012年10月—2013年9月污染气体和PM2．5的连续观测资料，结合HYSPLIT＿4轨迹模式计算得到的观测期间嘉兴不同季节的主导气团，分析了嘉兴市大气污染物的变化特征及不同季节下不同气团类型对该地污染物的影响．结果表明，嘉兴市CO、SO2、NO2和PM2．5日变化为双峰型分布，峰值位于07∶00—09∶00和16∶00—18∶00；O3呈单峰分布，峰值位于14∶00，这与人为活动和大气边界层变化密切相关．大气污染物具有显著的季节变化特征， SO2、CO 和 PM2．5冬季高（43．5，950．3，79．8μg·m－3），夏季低（21．5、522．4、38．0μg·m－3）；NO2在春季最高（49．9μg·m－3），夏季最低（30．4μg·m－3）；O3夏季最高（88．9μg·m－3），冬季最低（17?2μg·m－3）．影响嘉兴的主导气团的来源和路径存在显著季节变化，不同气团对大气污染物的分布影响较大，局地气团下SO2的浓度显著降低；大陆气团下污染物浓度普遍偏高，SO2、CO、NO2和PM2．5分别是海洋性气团的1．6—3．0、1．5—1．6、1．6—2．0和1．5—2．3倍；海洋性气团下污染物浓度普遍较低；混合性气团对应的污染物水平介于海洋性气团和大陆气团之间．

Based on the continuous observation of the gaseous pollutants and PM2.5 concentrations from October 2012 to September 2013 at the Environmental Monitoring Station of Jiaxing, the variations of air pollutants have been characterized, and the impacts of different air masses on the concentrations of CO, SO2, NO2, O3 and PM2.5 have been investigated by using the back?trajectory model HYSPLIT_4. Results showed that the diurnal variations of CO, SO2, NO2, and PM2.5 exhibited obviously bimodal distributions, peaking at 07∶ 00—09∶ 00 and 16∶ 00—18∶ 00, respectively, and showed a unimodal distribution for that of O3 with a peak at 14∶00, which could be related to the changes of human activities and atmospheric boundary. Besides, the air pollutants varied seasonally, with high levels in winter (43.5, 950.3, 79.8μg·m-3) and low levels in summer (21.5, 522.4, 38.0 μg·m-3) for SO2, CO and PM2.5, and a high level in spring (49.9 μg·m-3) and a low level in summer ( 30. 4 μg·m-3 ) for NO2 . O3 exhibited an opposite seasonality (88.9 μg·m-3 in summer and 17. 2 μg·m-3 in winter) to SO2, CO and PM2.5. The remarkable seasonal changes of prevailing air masses in the origin and transport pathway exert the impacts on the variations of air pollutants in Jiaxing. It is classified that the local air masses were related to a low SO2 level, however, the continental air masses usually contributed to high concentrations for SO2 , CO, NO2 and PM2.5, which were 1.6—3.0, 1.5—1.6, 1.6—2.0 and 1.5—2.3 times higher than those from the maritime air masses. The maritime air masses were related to a low pollution level, while the concentrations of pollutants influenced by the mixture air masses were generally higher than those from the maritime air masses and lower than those from continental air masses.