Articles | Volume 15, issue 16
Atmos. Chem. Phys., 15, 9577–9591, 2015

Special issue: Megapoli-Paris 2009/2010 campaign

Atmos. Chem. Phys., 15, 9577–9591, 2015

Research article 27 Aug 2015

Research article | 27 Aug 2015

In situ, satellite measurement and model evidence on the dominant regional contribution to fine particulate matter levels in the Paris megacity

M. Beekmann1, A. S. H. Prévôt2, F. Drewnick3, J. Sciare4,a, S. N. Pandis5, H. A. C. Denier van der Gon6, M. Crippa2, F. Freutel3, L. Poulain7, V. Ghersi8, E. Rodriguez9, S. Beirle10, P. Zotter2,b, S.-L. von der Weiden-Reinmüller3, M. Bressi4, C. Fountoukis5, H. Petetin1,8, S. Szidat11, J. Schneider3, A. Rosso8, I. El Haddad2, A. Megaritis5, Q. J. Zhang1,12, V. Michoud1,20, J. G. Slowik2, S. Moukhtar8, P. Kolmonen9, A. Stohl13, S. Eckhardt13, A. Borbon1, V. Gros4, N. Marchand14, J. L. Jaffrezo15, A. Schwarzenboeck16, A. Colomb1,16, A. Wiedensohler7, S. Borrmann3,17, M. Lawrence18,c, A. Baklanov19, and U. Baltensperger2 M. Beekmann et al.
  • 1LISA/IPSL, Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR CNRS 7583, Université Paris Est Créteil (UPEC) et Université Paris Diderot (UPD), Créteil, France
  • 2Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, PSI, Villigen, Switzerland
  • 3Particle Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
  • 4Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Laboratoire CEA-CNRS-UVSQ, Gif-sur-Yvette, France
  • 5Institute of Chemical Engineering Sciences (ICEHT), Foundation for Research and Technology Hellas (FORTH), Patra, Greece
  • 6Department of Climate, Air and Sustainability, TNO, Utrecht, the Netherlands
  • 7Leibniz Institute for Tropospheric Research, Leipzig, Germany
  • 8AIRPARIF, Agence de Surveillance de la Qualité de l'Air, Paris, France
  • 9Climate Change Unit, Finnish Meteorological Institute, 00101, Finland
  • 10Max Planck Institute for Chemistry, Satellite Group, Mainz, Germany
  • 11Department of Chemistry and Biochemistry & Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
  • 12Aria Technologies, Boulogne Billancourt, France
  • 13NILU – Norwegian Institute for Air Research, Kjeller, Norway
  • 14Laboratoire Chimie Provence, Equipe Instrumentation et Réactivité Atmosphérique (IRA), Université d'Aix-Marseille-CNRS, Marseille, France
  • 15Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), Université Joseph Fourier, CNRS, Grenoble, France
  • 16Laboratoire de Météorologie Physique (LaMP), Université Blaise Pascal, CNRS, Aubière, France
  • 17Institute of Atmospheric Physics, Johannes Gutenberg University Mainz, Mainz, Germany
  • 18Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz, Germany
  • 19Danish Meteorological Institute (DMI), Research Department, Copenhagen, Denmark
  • 20Mines de Douai, Douai, France
  • anow at: Energy Environment Water Research Center (EEWRC), The Cyprus Institute, Nicosia, Cyprus
  • bnow at: Lucerne School of Engineering and Architecture, Bioenergy Research, Lucerne University of Applied Sciences and Arts, 6048 Horw, Switzerland
  • cnow at: Institute for Advanced Sustainability Studies, Potsdam, Germany

Abstract. A detailed characterization of air quality in the megacity of Paris (France) during two 1-month intensive campaigns and from additional 1-year observations revealed that about 70 % of the urban background fine particulate matter (PM) is transported on average into the megacity from upwind regions. This dominant influence of regional sources was confirmed by in situ measurements during short intensive and longer-term campaigns, aerosol optical depth (AOD) measurements from ENVISAT, and modeling results from PMCAMx and CHIMERE chemistry transport models. While advection of sulfate is well documented for other megacities, there was surprisingly high contribution from long-range transport for both nitrate and organic aerosol. The origin of organic PM was investigated by comprehensive analysis of aerosol mass spectrometer (AMS), radiocarbon and tracer measurements during two intensive campaigns. Primary fossil fuel combustion emissions constituted less than 20 % in winter and 40 % in summer of carbonaceous fine PM, unexpectedly small for a megacity. Cooking activities and, during winter, residential wood burning are the major primary organic PM sources. This analysis suggests that the major part of secondary organic aerosol is of modern origin, i.e., from biogenic precursors and from wood burning. Black carbon concentrations are on the lower end of values encountered in megacities worldwide, but still represent an issue for air quality. These comparatively low air pollution levels are due to a combination of low emissions per inhabitant, flat terrain, and a meteorology that is in general not conducive to local pollution build-up. This revised picture of a megacity only being partially responsible for its own average and peak PM levels has important implications for air pollution regulation policies.

Short summary
A detailed characterization of air quality in the Paris (France) agglomeration, a megacity, during two summer and winter intensive campaigns and from additional 1-year observations, revealed that about 70% of the fine particulate matter (PM) at urban background is transported into the megacity from upwind regions. Unexpectedly, a major part of organic PM is of modern origin (woodburning and cooking activities, secondary formation from biogenic VOC).
Final-revised paper