用参评因子动态排序法评价环境综合质量

评价环境综合质量常用的方法是计算加权平均的综合指数，其中权重的确定又多用层次分析法（AHP）。设计以实际监测数据为依据计算两个参数yi1和yi2，并据此对各因子进行分类并排序，由此可定性确定各因子对环境总体污染的相对重要性，并判识环境污染中的关键因子、预警因子、趋好转的因子及可不必特别关注的因子；为定量确定各因子在综合评价中的权重，再依排序位次对其赋值，然后利用所赋之值进行因子间的两两比较以克服AHP法一般应用中因各人掌握标准有异而造成比较结果的不确定性，使权重确定完全建立在监测数据的客观基础上。此外，因环境污染状况随时空改变，若需对不同时段或不同区域的环境综合质量进行评价，给各因子赋予不变的权重显然不妥，而用上述思路和方法可依据实测值的差别对不同时段或不同区域的环境评价因子进行有根据的差异排序，然后再用AHP法定权，这就使不同时空环境质量的比较更为客观合理。

EVALUATION OF ENVIRONMENTAL COMPREHENSIVE QUALITY BY IMPROVED ANALYTICAL HIERARCHY PROCESS METHOD

Calculating arithmetic-weighted average value of environmental quality comprehensive index is a common method in environmental quality comprehensive evaluation.And the Analytical Hierarchy Process(AHP) method is a main method for determining its weight.In order to overcome the uncertainty due to different judgments based on different environmental information and criterion,an improved AHP method is designed for environmental quality comprehensive evaluation.The process of the improved AHP method involves the following key procedures.First the parameters y_i1 and y_i2 are calculated based on the environmental monitoring data.Second the pollution factors are put in order according to the symbol and value of y_i1 and y_i2.Third the different numerical value,which represents importance of each factor,is given to each pollution factor in light of seating order of factors.And forth the factor weights are achieved by the judgment matrix formed on the pairwise comparison of factors.Therefore,the weights of pollution factors are completely based on the monitoring data.Moreover,because the state of environmental pollution will change with time and space it is necessary to give different weight to each factor while evaluating environmental comprehensive quality in different periods and different regions.The improved AHP method can just be used to compare environmental comprehensive quality objectively among different periods and spaces.