重庆市大气污染物的空间统计分析

利用空间统计分析方法(spatial statistics analysis),借助GIS,分析了重庆市3种主要大气污染物TSP,SO₂和NO_x质量浓度在空间上的分布特点.研究表明,在"九五"期间和2002年2个时期,重庆市大气污染物在空间上均呈不均衡分布.整体上,SO₂的空间自相关性很强,属集中分布模式;TSP的空间自相关性较弱,属于随机分布模式;NO_x处于二者之间.局部相关性分析表明,大部分区县的大气污染物之间相关性较弱.此外,利用缓冲区和内插浓度表面法分析了2个时期的污染物质量浓度随离行政中心距离变化的趋势,发现ρ(TSP)和ρ(SO₂)在各地带内均有明显削减,而ρ(NO_x)削减不显著;ρ(SO₂)和ρ(NO_x)随距行政中心距离增大下降,但ρ(TSP)随距离增大而增加.3种污染物质量浓度都在离行政中心50～60 km的地带发生明显变化,由此得出目前重庆市大气污染物空间分布的特征距离为50～60km. 

The Spatial Statistic Analysis of Air Pollutants in Chongqing City

By employing the methods of spatial statistics and the tools of GIS, the spatial differential features about 3 main air pollutants, i.e. TSP, SO2 and NOx, were analyzed. It is concluded that air pollutants presented an uneven spatial distribution state in Chongqing City during two periods i.e. 1995-2000 and 2002. As a whole, the distribution of TSP takes on a random pattern, SO2 belongs to a clustered pattern and NOx stands in between TSP and NO,. Local autocorrelation analysis shows that the spatial autocorrelation among most districts of Chongqing City are faint. Moreover, buffering and interpolating analysis shows that only the mass concentrations of TSP and SO2 in every buffer reduce in the two periods, the mass concentrations of NO, does not reduce significantly, and that the mass concentrations of SO2 and NOx gradually decrease but the mass concentration of TSP gradually increases with the distance increasing from the centers of districts. The mass concentrations of the three pollutants all abruptly change at the distance of 50 - 60 km from the centers of districts, which means that the characteristic distance of air pollutants distribution in Chongqing City is 50 - 60 km.