This study aims on the analysis of the pollens’ phenological distributions in the greater area of Thessaloniki, over the years 2016-2020. The pollen index of the most contributable taxa of pollen spectrum is presented and is compared with similar studies. Τhe effect of the common Gaussian distribution on the diagnosis of the pollen concentrations is tested for Quercus taxa with the WRF-NEMO-CAMx modeling system. The modeling system consists of three models in series, the Weather Research and Forecasting (WRF) meteorological model, the Natural Emissions Model NEMO and the chemistry – transport model CAMx. The overall performance of the modelling system shows that oak pollen concentrations do not diverge significantly from those observed. In addition, regularity tests revealed a decreasing trend in timeseries, while exponential distribution proved to describe pollen concentrations with a small deviation in contrast with the Gaussian, which was used of its simplicity in pollen data analysis.