This study assesses the manner in which a North American urban area influences and modifies the dispersal of a regional pollen cloud and its concentration. Two different approaches are compared, one using classical statistics, the other employing modelling techniques. The passage of fronts that often increases the occurrence of regionalscale pollen peaks, while anticyclonic conditions appear to favour conditions for local pollen production but inhibit dilution on larger scales. Furthermore, a novel approach for aerobiology will involve numerical Regional Climate Model (RCM-NARCM) simulations to study pollen dispersal processes and how these are influenced by multiscale flows. Recent experiments with this model show that pollen concentrations are simulated in a realistic fashion and compare well to observations.