2001-2010年非洲大气PM2.5污染浓度空间格局演化

基于NASA的全球大气PM2.5年均污染浓度栅格数据，通过对非洲行政边界矢量化、分区统计各国大气PM2.5浓度均值及建立空间数据库，利用重力模型、ESDA模型及GIS空间统计分析方法，对非洲52个主要国家（地区）2001 – 2010年间的大气PM2.5污染浓度时空格局特征演化进行探究，并依据时间序列特征将研究对象划分为8类。研究结果表明：（1）2001-2010年非洲大气PM2.5污染浓度大致呈现“中间高、南北低；西部高、东部低”的空间特征；其中高值区集中分布在非洲西部几内亚湾附近的尼日利亚、刚果与喀麦隆等国家，低值区则广泛地分布在北非、南非以及非洲东南部印度洋沿岸地区或岛屿。（2）基于ESDA模型的空间自相关分析发现PM2.5浓度“高-高”热点区主要集聚在几内亚湾附近主要国家，“低-低”冷点区集中在东南部印度洋沿岸的南非、莫桑比克与马达加斯加岛。（3）时序上2001-2010年非洲PM2.5年平均污染浓度呈现明显下降趋势，其中32个国家（占研究区总数的61.54%）2010年PM2.5污染年均浓度低于2001年。（4）从自然环境条件及社会经济因素两方面浅析其空间格局主要成因：几内亚湾沿岸是非洲PM2.5污染最严重的地区，因其人口稠密且高度依赖石油产业；非洲东南部地区PM2.5污染最轻，得益于其良好的自然环境条件及低污染的支柱产业。

Spatial pattern evolution of annual average PM2.5 concentration in Africa, 2001-2010

Based on NASA’s global annual average PM2.5 grids, by vectoring the administrative boundaries of African countries, calculating the average con-centration of atmospheric PM2.5 of all countries and building the spatial database, using gravity model, ESDA model and GIS spatial statistical analysis method, we explore the spatial pattern evolution of the atmospheric PM2.5 pol-lution concentration of 52 main African countries from 2001 to 2010. According to their time series features, we classify them into 8 types. The results show that: (1) The concentration of atmospheric PM2.5 pollution in Africa generally shows the spatial characteristics of "middle high, north and south low; west high, east low" during 2001 to 2010. High concentration areas such as Nigeria, Congo and Cameroon, are mainly concentrated in the vicinity of the Gulf of Guinea in West Africa, and low concentration areas are widely distributed in North Africa, Southern Africa and coastal areas or islands of Southeast Africa.(2) Using spatial autocorrelation analysis method based on ESDA Model, we find that "High-High" type areas of PM2.5 concentrations are mainly dis-tributed in the major countries near Gulf of Guinea, and that "Low-Low" type areas of PM2.5 concentrations are concentrated in the countries of Southeast Africa such as South Africa, Mozambique and Madagascar. (3)The average annual PM2.5 concentrations in Africa decreased obviously from 2001 to 2010. Average annual PM2.5 pollution concentrations of 32 counties (accounted for 61.54% of total) in 2010 were lower than in 2001.(4) Due to high population density and dependence on the oil industry, countries near Gulf of Guinea are the areas with the highest PM2.5 concentration in Africa. On the contrary, the average PM2.5 concentrations of Southeast Africa is the lowest, thanks to their natural environment and low-pollution pillar industries.