An intensive soot aerosol characterisation campaign was organised in October 1999 at the large aerosol chamber facility AIDA in Karlsruhe, with the participation of scientists from nine Austrian, German, Russian, and Swiss Research Centres and Universities who contributed special equipment and expertise. The main goal was a comprehensive physical and chemical characterisation of soot aerosol from a modem turbo Diesel passenger car equipped with an oxidation catalyst, in comparison with artificial soot aerosol ("Palas" soot) from a commercial spark discharge generator which is often used as a surrogate for combustion soot in laboratory studies. Included were experiments with pure ammonium sulphate aerosol as well as its external mixtures with soot aerosols, and their evolution to partially internal mixtures on time scales up to 45 h. Effects of organic coatings on various aerosol properties, generated in situ by heterogeneous nucleation of products from the reaction of alpha-pinene with ozone were also investigated. The purpose of this paper is to present an overview of the whole campaign. This includes the description of technical and modelling tools, standard procedures, and the presentation of experimental parameters in tabular form, as a common background for a series of companion papers which focus on selected scientific issues. Included is a comparison between Diesel and spark generated soot in terms of their Raman and ESR spectra. The most remarkable difference is the large spin density in spark generated soot, which exceeds that of Diesel soot by an order of magnitude. However, the spin densities in both materials are too small to affect the surface properties of soot aerosols to a significant extent. (C) 2003 Elsevier Ltd. All rights reserved.