Sensitivity of ozone and aerosols to precursor emissions in Europe

We modelled the air quality in Europe during January and June 2006 using the MM5/CAMx model system and studied the sensitivity of ozone and aerosol formation to precursor emissions. Increased isoprene emissions by a factor of four in summer caused an increase in afternoon ozone by up to 10%. On the other hand, the effect on secondary organic aerosols (SOA) was very small. Reductions in NOx emissions are more effective to reduce ozone in a large part of Europe whereas anthropogenic VOC emission reductions are effective only around the urban areas. Particulate nitrate and organic aerosols are the main components of modelled PM2.5 concentrations in winter. In summer, organic aerosols dominate the aerosol composition. They are mainly secondary, produced from sesquiterpenes and monoterpenes as well as oligomerisation. Inorganic aerosol formation is more sensitive to ammonia emissions in winter. In summer, effects of NOx and NH3 emission reductions are lower because of lower ammonium nitrate concentrations.