A moment model to predict deposition rates of lognormally distributed aerosols onto cylindrical surfaces in cross flow was developed taking into account diffusion, thermophoresis and coagulation. The results of the moment model are in excellent agreement with the solution of Friedlander [Friedlander (1977) Smoke, Dust and Haze. Wiley, New York] for the limiting case of monodisperse aerosols in absence of coagulation. Deposition rates for polydisperse aerosols determined by the moment model are in good agreement with solutions obtained by integrating Friedlander's monodisperse aerosol results over the entire size distribution. Deposition rates have also been determined due to diffusion accounting for coagulation, and due to diffusion and thermophoresis accounting for coagulation having applicability in deposition of high concentration aerosols encountered in industrial systems such as manufacture of optical fibers by the OVD process or heat exchangers in boilers.