Wintertime aerosol chemical composition and source 1 apportionment of the organic fraction in the metrop olitan area 2 of Paris 3 4

Wintertime aerosol chemical composition and source 1 apportionment of the organic fraction in the metrop olitan area 2 of Paris 3 4 Crippa Monica , DeCarlo Peter F. , Slowik Jay G. , Mohr Claudia , Heringa Maarten 5 F. , Chirico Roberto , Poulain Laurent , Freutel Friederike , Sciare Jean , Cozic 6 Julie , Di Marco Chiara F. , Elsasser Michael , Nicolas José B. , Marchand 7 Nicolas , Abidi Ehgere , Wiedensohler Alfred , Drewnick Frank , Schneider 8 Johannes , Borrmann Stephan , Nemitz Eiko , Zimmermann Ralf , Jaffrezo Jean9 Luc , Prévôt Andre S. H. , Baltensperger Urs 1 10 11 [1]{Laboratory of Atmospheric Chemistry, Paul Scher rer Institute, PSI Villigen, 5232, 12 Switzerland} 13 [2]{Leibniz Institut for Tropospheric Research, Per moserstr 15, 04318, Leipzig, Germany} 14 [3]{Particle Chemistry Department, Max-Planck-Insti tu e for Chemistry, D-55128 Mainz, 15 Germany} 16 [4]{Laboratoire des Sciences du Climat et de l’Envi ronnement (LSCE/IPSL), Laboratoire CEA17 CNRS-UVSQ, 91191 Gif-sur-Yvette, France} 18 [5]{UJF – Grenoble 1 / CNRS, Laboratoire de Glaciol ogie et Géophysique de l’Environnement 19 (LGGE) UMR 5183, Grenoble, F-38041, France} 20 [6]{Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, United 21 Kingdom} 22 [7]{Joint Mass Spectrometry Centre, Cooperation Gr oup Comprehensive Molecular Analytics, 23 Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany} 24 [8]{Joint Mass Spectrometry Centre, Universität Ros tock, Institut für Chemie, Lehrstuhl für 25 Analytische Chemie, Dr.-Lorenz-Weg 1, 18059 Rostock } 26 [9]{ Aix-Marseille Université, CNRS, LCE FRE 3416, 13331, Marseille, France} 27 [10]{Institute for Atmospheric Physics, Johannes Gu tenberg University, Mainz, Germany} 28 [*]{now at: Department of Civil, Architectural, and Environmental Engineering, Drexel University, 29 Philadelphia, PA, USA, 19104} 30 [**]{now at Department of Atmospheric Sciences, Uni versity of Washington, Seattle WA 98195, 31 USA} 32 [***]{now at: Italian National Agency for New Techn ologies, Energy and Sustainable Economic 33 Development (ENEA), UTAPRAD-DIM, Via E. Fermi 45, 0 0 44 Frascati, Italy} 34 [****]{now at: WIL Research, 5203 DL 's-Hertogenbosch, The Netherl ands} 35 36 37 Correspondence to: A.S. H. Prévôt (andre.prevot@psi. ch) 38 39 Abstract 40 41 The effect of a post-industrial megacity on local a nd regional air quality was assessed via a month42 long field measurement campaign in the Paris metrop olitan area during winter 2010. Here we 43 present source apportionment results from three aer osol mass spectrometers and two aethalometers 44 deployed at three measurement stations within the P aris region. Submicron aerosol composition is 45 dominated by the organic fraction (30-36%) and nitr ate (28-29%), with lower contributions from 46 sulfate (14-16%), ammonium (12-14%) and black carbo n (7-13%). 47 Organic source apportionment was performed using po sitive matrix factorization, resulting in a set 48 of organic factors corresponding both to primary em ission sources and secondary production. The 49 dominant primary sources are traffic (11-15% of org anic mass), biomass burning (13-15%) and 50 Formatted: Font color: Auto