河北及周边地区霾污染特征的模拟研究

A modeling study of the regional haze over Hebei and surrounding areas

应用MM5-Models-3/CMAQ空气质量模拟系统对河北及周边地区进行了区域尺度的模拟,并选取石家庄、邢台、北京、天津、太原、郑州6个代表性城市分析了该地区霾污染特征.首先,通过气象观测数据对2001—2010年10年间的霾天气进行了识别,就统计结果来看,该地区霾污染的季节变化非常显著,冬季最为严重,其次是夏秋季;5月份的发生频率则最低,其次是4月和6月.选取霾污染较为严重的2007年12月进行了模拟,在模拟时段内,霾日的平均PM2.5浓度是非霾日的1.6～3.1倍,霾的发生有很明显的区域同步性.霾日PM2.5的成分也有显著变化,硫酸盐、硝酸盐等二次颗粒物的百分比含量有明显的增加,说明该地区霾的出现与二次颗粒物的形成有非常密切的关系.

MM5-Models-3/CMAQ air quality modeling system was applied to simulate the regional air pollution over Hebei and surrounding areas. Six cities, including Shijiazhuang, Xingtai, Beijing, Tianjin, Taiyuan and Zhengzhou, were chosen to analyze the characteristics of the regional haze in this area. First, the hazy days were identified for the ten years from 2001 to 2010. It was found that the haze occurrence showed clear seasonal variations. Thehaze pollution was the most serious in wintertime, followed by summer and autumn. The lowest frequencies appeared in May, then April and June. During the modeling period （ Dec. 2007）, the average PM2.5 concentrations in hazy days were 1.6 - 3.1 times of those in non - hazy days, and the occurrence of the hazy days in the six cities shewed very clear regionally synchronous characteristics. The compositions of PM2.5 in hazy days showed obvious differences as well. The concentrations of secondary particles such as sulfate and nitrate had a distinct increase in haze days, indicating that the secondary particles might be an important reason for the formation of the regional haze over Hebei and surrounding areas.