May 11, 2023 From April 17th to 27th, METAS ran a workshop calibrating the latest version of automated pollen monitors recently purchased by project partners and stakeholders. Three members of the SYLVA project consortium (MeteoSwiss, FMI and Swisens) provided METAS with instruments. Meteoswiss and Swisens joined the measurement campaign in person. The data is currently under evaluation and METAS will determine size dependent counting efficiencies of the three Poleno monitors based on the experiments, which will be compared with the theoretical calculations performed by Swisens. Preliminary data analysis showed good agreement.