Deposition micron and submicron particles onto a circular plate was studied numerically under special consideration of turbulence at low Reynolds number flows. Therefore a standard k-epsilon model was modified with a mixing length approach to describe the flow and particle concentration field in the vicinity of the surface. The investigated conditions, such as low flow velocities from the top to a horizontal surface, low turbulence levels and almost homogeneously distributed particles, are typical for a clean room environment. The calculated data were compared with the numerical data for the laminar case. An unexpected result was found, namely that turbulence causes only a negligible transport effect under these conditions. Only at the edge of the circular plate turbulence produced by the wall lead to an increasing deposition velocity. A second series of numerical analysis changing turbulence intensities of the incoming flow was performed by modelling a grid with known boundary conditions above the plate. In the particle size range below 0.1 mu m the increasing turbulence intensity caused an increase of the particle deposition rate. The desirable experimental verification of these numerical results does not seem appropriate because of the expected minimal deviation of the experimental data.