Reconstructing multi-decadal airborne birch pollen levels based on NDVI data and a pollen transport model

•Birch pollen monitoring stations provide reference data that are limited in time and space.•Chemistry Transport Models are capable to forecast high pollen levels over large areas.•Updating birch pollen emission sources over time and space is crucial in Chemistry Transport Models.•38 years of birch pollen emission source maps were constructed using NDVI data and Random Forest.