Representativeness of pollen traps: a review of the national pollen network of Switzerland

The national pollen network of Switzerland was developed historically. Its 14 pollen traps were placed without considering their representativeness and spatial coverage. The plan for automation of the network gives the motivation for reviewing the network design and to determine the importance and representativeness of each existing monitoring station. Similarities and dissimilarities of the 20-year-long pollen data series (1997–2016) were studied by cluster analysis. Focus was put on the daily course of the pollen season of the seven most important allergenic pollen taxa. The cluster analysis based on correlations of daily pollen concentrations revealed a group of seven similar stations on the Swiss Plateau which differ clearly from the seven stations outside this region. The stations on the Swiss Plateau can be clustered into two subregions, a western and an eastern one. Their correlation coefficients are linearly correlated with distance (from 50 to 300 km). The pattern of the clusters is in good agreement with the division of Switzerland in bioclimatic regions.