New mathematical model of laminar flow diffusion chamber (LFDC) performance is proposed, which includes mutial influence of homogeneous (heterogeneous) nucleation and droplets growth on heat and mass transfer processes. Qualitative investigation of heat and mass transfer processes and their influence on droplets growth is made. The limits of applicability of earlier mathematical model of LFDC are established. The numerical simulation of new mathematical model of the performance LFDC is presented. It is discovered that the nature of carrier gas substantially affects on the volume of nucleation zone in LFDC. In particular, for argon as the carrier gas the volume of nucleation zone is on the order above then for helium as the carrier gas. Effects of local structure of supersaturation field near growing droplets are discussed. Their application for interpretation of experimental data is proposed. (c) 2005 Elsevier Ltd. All rights reserved.