1 Operational model evaluation for particulate matter in Europe and North America in the context of the AQMEII project Efisio Solazzo 1, ,Roberto Bianconi 2 ,Guido Pirovano 6,7 , Volker Matthias 17 , Robert Vautard 3 , K. Wyat Appel 9 , Bertrand Bessagnet 6 , Jørgen Brandt 16 , Jesper H. Christensen 16 , Charles Chemel 11,12 , Isabelle Coll 15 , Joana Ferreira 8 , Renate Forkel 10 , Xavier V. Francis 12 , George Grell 18 , Paola 5 Grossi 2 , Ayoe Hansen 16 , Ana Isabel Miranda 8 , Michael D. Moran 14 , Uarporn Nopmongcol 4 , Marje Parnk 19 , Karine N. Sartelet 5 , Martijn Schaap 20 , Jeremy D. Silver 16 , Ranjeet S. Sokhi 12 , Julius Vira 19 , Johannes Werhahn 10 , Ralf Wolke 13 , Gregg Yarwood 4 , Junhua Zhang 14 , S.Trivikrama Rao 9 , Stefano Galmarini 1, * 10 1 Joint Research Centre, European Commission, ISPRA, Italy; 2 Enviroware srl, via Dante 142, 20863 Concorezzo (MB), Italy 3 IPSL/LSCE Laboratoire CEA/CNRS/UVSQ 4 Environ International Corporation, Novato CA, USA 5 CEREA, Joint Laboratory Ecole des Ponts ParisTech/ EDF R & D, Université Paris-Est, France 15 6 Ineris, Parc Technologique Halatte, France 7 Ricerca sistema energetico (RSE), Italy 8 CESAM & Department of Environment and Planning, University of Aveiro, Aveiro, Portugal 9 Atmospheric Modelling and Analysis Division, Environmental Protection Agency, NC, USA 10 IMK-IFU, Institute for Meteorology and Climate Research-Atmospheric Environmental Division, Germany 20 11 National Centre for Atmospheric Science (NCAS), University of Hertfordshire, Hatfield, UK 12 Centre for Atmospheric & Instrumentation Research (CAIR), University of Hertfordshire, Hatfield, UK 13 Leibniz Institute for Tropospheric Research, Leipzig, Germany 14 Air Quality Research Division, Science and Technology Branch, Environment Canada, Toronto, Canada 15 IPSL/LISA UMR CNRS 7583, Université Paris Est Créteil et Université Paris Diderot 25 16 Department of Atmospheric Environment, National Environmental Research Institute, Aarhus University, Denmark 17 Institute of Coastal Research, Helmholtz-Zentrum Geesthacht,Geeshacht, Germany 18 CIRES-NOAA/ESRL/GSD National Oceanic and Atmospheric Administration Environmental Systems 30 Research Laboratory Global Systems Division Boulder, Colorado USA 19 Finnish Meteorological Institute, Helsinki, Finland 20 Netherlands Organization for Applied Scientific Research (TNO), Utrecht, The Netherlands 35 * Author for correspondence: S.Galmarini. Email: Stafano.Galmarini@jrc.europa.eu