A computational fluid dynamics based sectional aerosol model is introduced. One of the motivations and the first test case is the simulation of aerosol formation via nucleation in laminar flow reactors. Simulation results are compared with experiments and simulations with other modelling concepts presented in the literature. The main scheme is based on a boundary layer type solution of sectional aerosol equations that uses flow fields provided a computational fluid dynamics (CFD) code. Special attention has been paid to the computational aspects and it is demonstrated that the scheme yields accurate grid-independent solutions in reasonable computation times. An alternative method based on full sectional Eulerian simulation has also been developed. Due to excessive demands on CFD grid resolution, an attempt to simulate aerosol formation in a laminar flow reactor with this scheme failed to provide accurate predictions. (C) 2000 Elsevier Science Ltd. All rights reserved.