Maritime traffic is constantly increasing and is unlikely to decrease in the years to come. However, merchant and tourist ships still use fuels with a high pollutant content, particularly in the Mediterranean sea where regulations are more flexible than those applied in northern European waters. The pollutants of interest in this work, which include particulate matter (PM10, PM2.5), NO2, SO2 and ozone, are responsible for respiratory diseases such as airway irritation, cardiopulmonary and lung cancers. The purpose of this study is to estimate the impact of marine traffic on the air quality of Marseille in case of high occupancy scenarios of the port. In order to do so, we have parameterized the numerical weather forecasting model WRF (Weather Reasearch and Forecasting) that allows the inclusion of chemistry and atmospheric transport equations. The chemical model takes yearly chemical emission data from EDGAR-HTAP inventory. Hourly coefficients are then applied accordingly to the method implemented by Crippa et al. [5]. For ship traffic, AIS data provides position, speed or time at berth of any given boat as well as its main features. Methodology to estimate ship emissions is derived from both EMEP/EEA [6] and EPA [8] reports. The relative difference in concentration between a situation with and without ship traffic allows us to evaluate the influence of ships on air quality. The effect of seasonality is also analyzed, by running 4 simulations of 72 hours for each season. When compared to the values presented in Viana et al. [22], the model seems to underestimate the contribution of the shipping sector to urban pollution for gas species, estimated around 1% for SO2, NO2 and O3. However, PM10 and PM2.5 contribution levels are consistent with previous studies, with values ranging from 3.5% to 12.8%.