The aim of this article is to contribute to the qualitative description of the phenomena occurring during the clogging of fibre filters by submicron liquid particles. The changes in the pressure drop and efficiency of the filtration media in relation to the generated aerosol mass per unit area were monitored simultaneously. The different experimental approaches described converge on the same description of filter clogging, the scenario being broken down into four steps. A study of the influence of the operating conditions was carried out which highlighted the significant roles of filtration velocity, the nature of the filter, and the physico-chemical characteristics of the aerosol. (C) 2003 Elsevier Ltd. All rights reserved.