Summary The regional patterns of PAH-concentrations in NE-Bavarian snow may be explained as follows: snow scavenges PAH over urban centres and orographic uplifting of air over mountains increases the scavenging by snow. By multivariate statistical analysis it could be shown that the influence of heating on the PAH-concentrations in snow is stronger than that of combustion by traffic. As all PAH load only one single principal component, a constant qualitative PAH pattern is evident. This allows to reduce the measurements of PAH to only one for each sample.