VDI 3957 Blatt 6:2003-04 (R2015)

It is possible to determine concentrations of important pollution components individually with chemico-physical methods. These components, however, represent only a limited selcetion of all factors that occur in the environment and are relevant to the effect on plants. The prdiction of an integrated total effect using physico-chemical concentration measurements of individual pollution components suffersfrom substantial uncertainty, even if the parallel influence of climatic factors is considered. By contrast the results of biological measurement methods are incomparably more reliable than predictions of effects dreived from technical poolution measurements because the determined effects provide direct information on the detrimental effects on the effected object, of which some are plants. For long time the indication of photooxidant effects has been of special importance for the effect measurements with bioindicators.