The ability of organic compounds to grow small atmospheric nuclei via condensation was investigated. The investigation was,based on theoretical considerations and model simulations. The results indicate that the condensational, growth of atmospheric nuclei having diameters. < 10 nm requires the presence of compounds that are able to move irreversibly from the gas phase into these nuclei. The required saturation vapour pressure to make a,compound to behave this way is dependent on the nucleus diameter, as well as on the nucleus composition and the phyico-chemical properties of the condensing compound. The estimates are applied to identify which organic vapours might induce the growth of small nuclei in the atmosphere. Furthermore, various implications of the obtained results are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.