Assessing Sensitivity Regimes of Secondary Inorganic Aerosol Formation in Europe with the CALIOPE-EU Modelling System

Abstract

Sulphur dioxide (SO2) and nitrogen oxides (NOx) form two of the largest contributors to PM2.5 in Europe: ammonium sulphate, (NH4)2SO4, and ammonium nitrate, NH4NO3. Understanding the formation regimes for these components is important for the achievement of the reduction objectives established in the European legislation for PM2.5. The present work uses the CALIOPE air quality forecasting system to investigate the formation of secondary inorganic aerosols (SIAs) and their gaseous precursors over Europe. Results points out that the continental regions in Europe tend to be HNO3- limited for nitrate formation. Regulatory strategies in such regions should focus on reductions in NOx rather than NH3 to control NH4NO3. © Springer Science+Business Media Dordrecht 2014.