环境监测3种不确定度评定方法的比较——以水中化学需氧量的测定为例

Comparison of Three Uncertainty Evaluation Methods for Environmental Monitoring——Taking the Determination of Chemical Oxygen Demand in Water as an Example

利用环境监测实验室积累的数据,通过线性拟合法、GUM法和控制图法对水中化学需氧量的不确定度进行了评定。结果表明:3种不确定度评定方法的评定结果相似。在量化过程中存在两种主要不确定度评定的类型:一种是不确定度的正向传播,另一种是模型不确定度和参数不确定度的反向评定。GUM法明显是正向的不确定度,线性拟合法和控制图法是反向不确定度。GUM法应用复杂且烦琐,操作性差;相比,控制图法和线性拟合法更加简单实用,可代替GUM法来评估监测实验室的不确定度。

Utilizing the data accumulated in the environmental monitoring laboratory,the uncertainty of chemical oxygen demand inwater was evaluated by linear fitting method,GUM method and control chart method. The results showed similarity of the three un-certainty evaliition method. There are two main types of uncertainty evaliaaion in the quantification process： one gation of uncertainty and the otlier is the inverse assesment of model uncertainty ously forward uncertainty, linear fitting method and control graph method are inverse unccrtainty. GUM method is complex and cum- bersome, and it is hard to manipulate. In contrast, the control chart method and linear fitting methodare moresimple and practical, they can be the replaccment of GUM method to assess the uncrtainty of the