Articles | Volume 12, issue 18
Atmos. Chem. Phys., 12, 8663–8677, 2012

Special issue: The Pan European Gas-Aerosols Climate Interaction Study...

Atmos. Chem. Phys., 12, 8663–8677, 2012

Research article 26 Sep 2012

Research article | 26 Sep 2012

Simulating ultrafine particle formation in Europe using a regional CTM: contribution of primary emissions versus secondary formation to aerosol number concentrations

C. Fountoukis1, I. Riipinen2, H. A. C. Denier van der Gon3, P. E. Charalampidis4, C. Pilinis4, A. Wiedensohler5, C. O'Dowd6, J. P. Putaud7, M. Moerman3, and S. N. Pandis1,8,9 C. Fountoukis et al.
  • 1Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas (ICEHT/FORTH), Patras, Greece
  • 2Department of Applied Environmental Science & Bert Bolin Centre for Climate Research, Stockholm University, 11418 Stockholm, Sweden
  • 3Netherlands Organisation for Applied Scientific Research TNO, Princetonlaan 6, 3584 CB Utrecht, The Netherlands
  • 4Department of Environment, University of the Aegean, University Hill, 81100, Mytilene, Greece
  • 5Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany
  • 6School of Physics and Centre for Climate & Air Pollution Studies, National University of Ireland Galway, University Road, Galway, Ireland
  • 7European Commission, Joint Research Centre, Institute of Environment and Sustainability, Ispra, Italy
  • 8Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
  • 9Department of Chemical Engineering, University of Patras, Patras, Greece

Abstract. A three-dimensional regional chemical transport model (CTM) with detailed aerosol microphysics, PMCAMx-UF, was applied to the European domain to simulate the contribution of direct emissions and secondary formation to total particle number concentrations during May 2008. PMCAMx-UF uses the Dynamic Model for Aerosol Nucleation and the Two-Moment Aerosol Sectional (TOMAS) algorithm to track both aerosol number and mass concentration using a sectional approach. The model predicts nucleation events that occur over scales of hundreds up to thousands of kilometers especially over the Balkans and Southeast Europe. The model predictions were compared against measurements from 7 sites across Europe. The model reproduces more than 70% of the hourly concentrations of particles larger than 10 nm (N10) within a factor of 2. About half of these particles are predicted to originate from nucleation in the lower troposphere. Regional nucleation is predicted to increase the total particle number concentration by approximately a factor of 3. For particles larger than 100 nm the effect varies from an increase of 20% in the eastern Mediterranean to a decrease of 20% in southern Spain and Portugal resulting in a small average increase of around 1% over the whole domain. Nucleation has a significant effect in the predicted N50 levels (up to a factor of 2 increase) mainly in areas where there are condensable vapors to grow the particles to larger sizes. A semi-empirical ternary sulfuric acid-ammonia-water parameterization performs better than the activation or the kinetic parameterizations in reproducing the observations. Reducing emissions of ammonia and sulfur dioxide affects certain parts of the number size distribution.

Final-revised paper