华北地区空气质量空间分布特征及成因研究

以2015年华北地区71个主要城市的AQI监测数据为基础,通过交叉验证评估不同空间插值方法,选择克里金指数模型生成华北地区的AQI栅格数据;然后分析区域AQI的时空分布特征,并重点讨论了降水、风向、风速及地形对AQI的影响;最后利用逐步回归分析法,找出对AQI产生较大影响的社会经济因子,并结合ESDA方法和空间回归模型对AQI及社会经济因子进行空间相关性分析.结果表明:AQI的几种插值方法中以克里金指数插值法精度整体最优;AQI有明显的季节性变化,冬季AQI明显高于夏季;华北地区整体污染较重,最严重的区域集中在河北南部、河南北部和山东西部;降水、风和地形与AQI关系密切,当降水量大于10 mm时,对AQI具有显著的抑制作用;AQI与风速呈显著负相关,风速对不同污染物的影响强度具有明显的季节差异,冬季偏北风向是造成空气污染南移和扩散的主要原因;太行山脉和燕山山脉阻塞污染物向西和向北扩散,导致华北平原的东南部地区污染加重;社会经济因子中,工业对AQI的影响最大,其他依次为民用汽车保有量、人口密度、森林覆盖率.

Study on the spatial distribution characteristics and the drivers of AQI in North China

Based on the monitoring data of air quantity index (AQI) in 71 major cities of North China in 2015, this paper assesses seven typical spatial interpolation methods by cross-validation and uses Kriging with exponential model to produce the raster data of AQI in North China. It discusses the spatial and temporal distribution characteristic of AQI in this region, focuses on the effect of precipitation, wind speed, wind direction and topography on AQI. A forward-selection stepwise regression model is designed to explore the major factors which concern the socio-economic impact on AQI, and the spatial correlation between AQI and socio-economic factors is discovered using the method of exploratory spatial data analysis(ESDA) combined with spatial regression model. The research shows that, 1 Kriging, especially Kriging with exponential model, has higher precision than other methods for the interpolation of AQI. 2 AQI has sharp distinction between four seasons. It is much higher in winter than that in summer. 3 Severe pollution is popular in North China. The severest regions are the south of Hebei, north of Henan, and west of Shandong. 4 Precipitation, wind, and topography have apparent impact on AQI. AQI declines significantly when daily precipitation is greater than 10 mm.It is negative correlation between AQI and wind speed.The influence of wind speed on different pollutants has obvious seasonal difference.North wind causes the movement and spread of air pollution in winter and lead to pollution incidents in southern areas.The mountains of Taihang and Yanshan limit the spread of pollution toward west and north, and cause the pollution in the plain area of southeast is much serious.5 Socio-economic factors also contribute to AQI. The second industry is the most significant factor, the others include civilian vehicles, population density, and percentage of forest in descending order.