Articles | Volume 9, issue 8
Geosci. Model Dev., 9, 2741–2754, 2016
Geosci. Model Dev., 9, 2741–2754, 2016

Development and technical paper 22 Aug 2016

Development and technical paper | 22 Aug 2016

Implementation of state-of-the-art ternary new-particle formation scheme to the regional chemical transport model PMCAMx-UF in Europe

Elham Baranizadeh1, Benjamin N. Murphy2,a, Jan Julin1,2, Saeed Falahat2,b, Carly L. Reddington3, Antti Arola4, Lars Ahlm2, Santtu Mikkonen1, Christos Fountoukis5, David Patoulias6, Andreas Minikin7,c, Thomas Hamburger8,d, Ari Laaksonen1,9, Spyros N. Pandis6,10,11, Hanna Vehkamäki12, Kari E. J. Lehtinen1,4, and Ilona Riipinen2 Elham Baranizadeh et al.
  • 1Aerosol Physics Group, Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
  • 2Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, Stockholm, Sweden
  • 3Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
  • 4Atmospheric Research Centre of Eastern Finland, Finnish Meteorological Institute, Kuopio, Finland
  • 5Qatar Environment and Energy Research Institute (QEERI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
  • 6Department of Chemical Engineering, University of Patras, Patras, Greece
  • 7Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
  • 8Atmosphere and Climate Department (ATMOS), Norwegian Institute for Air Research (NILU), Oslo, Norway
  • 9Climate research Unit, Finnish Meteorological Institute, Helsinki, Finland
  • 10Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas (ICEHT/FORTH), Patras, Greece
  • 11Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
  • 12Division of Atmospheric Sciences, Department of Physics, University of Helsinki, Helsinki, Finland
  • anow at: the National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, Durham, NC, USA
  • bnow at: the Swedish Meteorological and Hydrological institute (SMHI), Norrköping, Sweden
  • cnow at: Deutsches Zentrum für Luft- und Raumfahrt (DLR), Flugexperimente, Oberpfaffenhofen, Germany
  • dnow at: Federal Office for Radiation Protection (BfS), Neuherberg, Germany

Abstract. The particle formation scheme within PMCAMx-UF, a three-dimensional chemical transport model, was updated with particle formation rates for the ternary H2SO4–NH3–H2O pathway simulated by the Atmospheric Cluster Dynamics Code (ACDC) using quantum chemical input data. The model was applied over Europe for May 2008, during which the EUCAARI-LONGREX (European Aerosol Cloud Climate and Air Quality Interactions–Long-Range Experiment) campaign was carried out, providing aircraft vertical profiles of aerosol number concentrations. The updated model reproduces the observed number concentrations of particles larger than 4 nm within 1 order of magnitude throughout the atmospheric column. This agreement is encouraging considering the fact that no semi-empirical fitting was needed to obtain realistic particle formation rates. The cloud adjustment scheme for modifying the photolysis rate profiles within PMCAMx-UF was also updated with the TUV (Tropospheric Ultraviolet and Visible) radiative-transfer model. Results show that, although the effect of the new cloud adjustment scheme on total number concentrations is small, enhanced new-particle formation is predicted near cloudy regions. This is due to the enhanced radiation above and in the vicinity of the clouds, which in turn leads to higher production of sulfuric acid. The sensitivity of the results to including emissions from natural sources is also discussed.

Short summary
The molecular mechanisms through which new ultrafine (< 100 nm) aerosol particles are formed in the atmosphere have puzzled the scientific community for decades. In the past few years, however, significant progress has been made in unraveling these processes through laboratory studies and computational efforts. In this work we have implemented these new developments to an air quality model and study the implications of anthropogenically driven particle formation for European air quality.