中国地级以上城市SO_2年均质量浓度时空特征分析

Spatial and temporal distributions of SO_2 concentration in China’s prefecture-level cities

"十一五"期间,我国SO2等污染物的污染形势得到初步遏制,但是SO2依然是大气污染的重要污染物之一。研究地级以上城市SO2年均质量浓度的时间和空间分布特性,了解其时空分布规律,对于重点区域大气污染防治规划的落实和SO2污染防治具有一定的参考意义。在汇总整理2007—2010年我国地级以上城市SO2年均质量浓度的基础上,初步定性分析了其年度变化规律,并分析了2010年333个城市SO2质量浓度的空间分布规律;然后应用数学方法定量分析,重点应用重心迁移的方法分析了2007—2010年地级以上城市SO2年均质量浓度重心的变化;应用全局空间自相关分析和局部空间自相关分析研究2010年地级以上城市的整体聚集特性和局部聚集特性,用Moran’s I指数表征整体聚集度,Lisa值表征局部聚集度。结果表明,2007—2010年4年间,我国地级以上城市SO2严重污染的趋势得到遏制,其年均质量浓度大于空气三级质量浓度标准的城市比例显著降低;污染重心在中部偏南的湖南省境内,并存在西南向的微弱移动。2010年SO2污染具有一定的聚集特性,全局聚集度指数为0.45;局部聚集明显,其中华北平原、内蒙古高原的城市为SO2高污染的聚集区,其次是四川盆地和云贵高原的部分城市。因此,需要加强控制华北平原、内蒙古高原、云贵高原、四川盆地的SO2污染。区域联防联控,遏制污染向西部地区转移,对于我国大气污染防治、提高空气质量非常重要。

The SO2 emission has been gradually reduced during the ＂11 th Five-Year＂ period, but SO2 is still one of the most important pollutants in China. It is significant to study the spatial and temporal variations of SO2 concentration for the implementation of regional air pollution prevention and control planning. In this study, we analyzed the annual variation of SO2 concentration from the year 2007 to 2010 and the spatial distributions of SO2 concentration in 333 cities in the year 2010. Then, the center-of-gravity migrating approach was used to analyze the center of gravity change of SO2 concentration during the year 2007 to 2010. Through the overall and local spatial autocorrelation analysis the Moran＇s index and Lisa values were respectively estimated to analyze the overall aggregation degree and local aggregation degree of SO2 pollution. The results indicated that SO2 pollution has been gradually alleviated and SO2 concentrations of more cities were lower than Class [II of China＇s Air Quality Stantards. The center-of-gravity of SO2 pollution was in middle-south of Hunan province and was slowly moving to the northwest direction. In 2010, the overall aggregation degree was 0.45 and the highest aggregation area of SO2 pollution was located in North China Plain, Inner Mongolia Plateau, followed by Sichuan Basin and Yun-Gui Plateau. The lowest pollution aggregation area was in the southeast coast area. Therefore, it is important to further control the SO2 pollution in the North China Plain, Inner Mongolia Plateau, the Yun-Gui Plateau and Sichuan Basin. We also recommended to adopt regional joint pollution abatement strategy to alleviate the migration of SO2 pollution to the western regions.