J. Phys. IV France 107 (2003) 521
DOI: 10.1051/jp4:20030355

Evidences of modifications in the size distribution of particles during a mercury depletion event at Kuujjuarapik/Whapmagoostui, Québec (Canada)

P.-A. Gauchard¹, G. Guehenneux², C.P. Ferrai^{1, 3}, L. Poissant⁴, A. Dommergue¹, C.F. Boutron^{1, 5}, M.-C. Fourcade^{1, 6} and P. Baussand<sup>6

1</sup>  Laboratoire de Glaciologie et Géophysique de l'Environnement du CNRS, 54 rue Molière, Domaine Universitaire, BP. 96, 38402 Saint-Martin-d'Hères, France
²  Groupe de Recherche sur l'Environnement et la Chimie Atmosphérique, 39-41 boulevard Gambetta, 38000 Grenoble, France
³  École Polytechnique Universitaire de Grenoble, Université Joseph Fourier, 28 avenue Benoît Frachon, BP. 53, 38041 Grenoble, France
⁴  Processus Atmosphériques des Toxiques, Service Météorologique du Canada, Environnement Canada, 105 rue McGill, 7e Étage (Youville), Montréal, Québec H2Y 2E7, Canada
⁵  Unités de Formation et de Recherche de Mécanique et de Physique, Université Joseph Fourier, Institut Universitaire de France, Domaine Universitaire, BP. 68, 38041 Grenoble, France
⁶  Laboratoire de Génie Analytique, Conservatoire National des Arts et Métiers, 292 rue Saint-Martin, 75141 Paris cedex 03, France

Abstract
During a field experiment at Kuujjuarapik/Whapmagoustui (55°31N, 77°75W), Québec, we have pointed out modifications in the size distribution of particles during a Mercury Depletion Event (MDE). We observed an increase of atmospheric particles concentrations in the ambient air, correlated with depletions of ozone and atmospheric mercury. These increases were followed by a change in the size particles distribution. Assuming that the divalent mercury species formed during the MDE could be adsorbed onto particles, this is likely to contribute to higher deposition fluxes of oxidised mercury on the snow pack.

© EDP Sciences 2003