1Department of Chemical Engineering, University of Patras, Patras, Greece
2Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Patras, Greece
3Department of Environment, University of the Aegean, University Hill, 81100, Mytilene, Greece
4Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
Abstract. PMCAMx-2008, a three dimensional chemical transport model (CTM), was applied in Europe to quantify the changes in fine particle (PM2.5) concentration in response to different emission reductions as well as to temperature increase. A summer and a winter simulation period were used, to investigate the seasonal dependence of the PM2.5 response to 50% reductions of SO2, NH3, NOx, anthropogenic VOCs and anthropogenic OA emissions and also to temperature increases of 2.5 and 5 K. Reduction of NH3 emissions seems to be the most effective control strategy for reducing PM2.5, in both periods, resulting in a decrease of PM2.5 up to 5.1 μg m−3 and 1.8 μg m−3 (5.5% and 4% on average) during summer and winter respectively, mainly due to reduction of NH4NO3 (20% on average in both periods). The reduction of SO2 emissions decreases PM2.5 in both periods having a significant effect over the Balkans (up to 1.6 μg m−3) during summer, mainly due to decrease of sulfate (30% on average over the Balkans). The anthropogenic OA control strategy reduces total OA by 15% during winter and 8% in the summer. The reduction of total OA is higher in urban areas close to its emissions sources. A slight decrease of OA (8% in summer and 4% in winter) is also predicted after a 50% reduction of VOCs emissions due to the decrease of anthropogenic SOA. The reduction of NOx emissions reduces PM2.5 (up to 3.4 μg m−3) during the summer, due a decrease of NH4NO3, causing although an increase of ozone concentration in major urban areas and over Western Europe. Additionally, the NOx control strategy actually increases PM2.5 levels during the winter. The increase of temperature results in a decrease of PM2.5 in both periods over Central Europe, mainly due to a decrease of NH4NO3 during summer (18%) and fresh POA during winter (35%). Significant increases of OA are usually predicted during summer due mainly to the increase of biogenic VOC emissions. On the contrary, OA is predicted to decrease in the winter due to the dominance of fresh POA reduction and the small biogenic SOA contribution to OA. The resulting increase of oxidant levels from the temperature rise lead to an increase of sulfate levels in both periods, mainly over North Europe and the Atlantic Ocean. The substantial reduction of PM2.5 components due to emissions reductions of their precursors in conjunction with significant changes of PM after increasing the temperature indicate that both emissions and temperature need to be of significant concern for improving air quality.