ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-4-2499-2004 Evolution of organic and inorganic components of aerosol during a Saharan dust episode observed in the French Alps Aymoz G. 1 Jaffrezo J.-L. 1 Jacob V. 2 Colomb A. 2 4 George Ch. 3 Laboratoire de Glaciologie et Géophysique de l’Environnement (LGGE-CNRS), 54 rue Molière, 38402 Saint Martine D’Hères Cedex, France Groupe de Recherche en Environnement et Chimie Appliquée (GRECA) IUT de Chimie, UJF, 39–41 Bd Gambetta, 38000 Grenoble, France Laboratoire d’Application de la Chimie à l’Environnement (UCLB-CNRS), 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne, France now at: Max Planck Institut für Chemie, Postfach 3060, 55020 Mainz, Germany 09 12 2004 4 11/12 2499 2512 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/4/2499/2004/acp-4-2499-2004.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/4/2499/2004/acp-4-2499-2004.pdf

A Saharan dust event was observed in a rural area in the Maurienne Valley (French Alps) in summer 2000. Detailed data on PM<sub>10</sub>, particle numbers, and aerosol chemistry (ionic species and Elemental Carbon (EC) and Organic Carbon (OC)) are presented. The comparative evolutions of particle numbers and chemistry (calcium, sodium, and sulfate) show that the overall period included two episodes of dust particles with very distinct chemistry, followed by an episode with a large increase of the concentrations of species with an anthropogenic origin. The overall data set does not indicate large interactions between the dust particles and compounds from anthropogenic origin (sulfate, nitrate) or with organic carbon, all of these species showing very low concentrations. Simplistic calculations indicate that these concentrations are consistent with our current knowledge of adsorption processes of gases on mineral dust in a clean air mass.