Anthropogenic Emission Scenarios over Europe with the WRF-CHIMERE-v2020 Models: Impact of Duration and Intensity of Reductions on Surface Concentrations during the Winter of 2015

In the framework of the FAIRMODE initiative, a set of simulations was performed using the WRF and CHIMERE models. The simulation period is chosen to cover a Particulate Matter (PM) pollution episode that happened in February 2015 over the Parisian area. A thorough validation of the reference simulation is presented, showing a good agreement between the measurements and the model both for PM components and major gaseous species. The PM composition analysis shows that the major contributors to the PM total concentration are nitrates and organic aerosols, followed by ammonium. An analysis of emission reduction scenarios compared to the reference simulation is also presented and different configurations of these scenarios are analyzed. Exceedances regarding to the last World Health Organization (WHO) guidelines are assessed, concluding that even if the most severe mitigation analyzed here (−50% emissions reduction) was applied over Paris, exceedances would still happen for PM. Emission reduction scenarios show that ozone concentrations are sensitive to NOx reductions inside the city with an increase in concentrations, while for PM a systematic decrease is observed whichever precursor emission is reduced. Coupling effects are explored and the impact of PM concentrations on the radiative and thermodynamic budgets is quantified. Scenarios are repeated both with different durations and different intensities and the most efficient configuration leading to exceedances reduction is discussed.