Submicronic aerosol dry deposition non urban surfaces: a wind tunnel study to improve the lack of knowledge

1 ppInternational audienceIn the case of an accidental or chronic atmospheric pollution by a nuclear plant, and to determine the impact of aerosols contained in the plume on urban areas, aerosols deposition transfer oefficients must be known for the different types of urban surfaces. In dry atmospheric conditions, these coefficients are defined by the dry deposition velocities Vd (m.s-1), the ratio between aerosol vertical dry deposition flux (particles.m-2.s-1) and concentration of aerosols (particles.m-3) (Seinfeld and Pandis, 1998). Dry deposition velocities are dependent on atmospheric turbulent conditions and surface roughness. Actually, for urban surfaces, there are few dry deposition velocities measured, in field or in laboratory, and existing data are not linked with atmospheric conditions (Fowler et al, 2009). Therefore, it is important to improve the knowledge and the models on urban areas. The aim of this wind tunnel study is to quantify, experimentally, dry deposition velocities for a submicron aerosol on three urban surfaces, for three wind speeds (Uref), and to measure turbulence in the wind tunnel, especially friction velocities U*