High resolution modeling of Quercus pollen with an Eulerian modeling system: A case study in Greece

In this study a high resolution modeling system is developed to simulate Quercus pollen concentrations in the greater area of Thessaloniki, Greece, under an a priori oak phenological season. The modeling system consists of three models in series, the Weather Research and Forecasting (WRF) meteorological model, the natural emissions model NEMO for Quercus pollen emissions and the chemistry-transport model CAMx. The modeling system is evaluated with daily meteorological and pollen measurements during the phenological season of 2016 of Quercus taxa. The modeling system's performance is satisfactory on both meteorology and Quercus pollen concentrations, although for the latter the relative uncertainty is slightly above the 50% criterion usually applied in air quality modeling. Additional analysis was performed on three parameters related to pollen emissions, namely the assigned pollen production, the spread of the phenology and the assigned diameter. The analysis shows that the greatest impact on Quercus pollen concentrations, on both near the sources as well at remote areas, is the assigned pollen production, followed by the spread and the assigned diameter.