In this work, we study the interaction between small water aggregates and hydroxylated graphite surfaces by means of quantum calculations. The hydroxylated graphite surfaces are modelled by anchoring OH groups on the face side or on the edges of a graphite crystallite of nanometer size. The quantum calculations based on the ONIOM approach aim at characterizing the adsorption properties (structure and adsorption energy) of small water aggregates containing up to five water molecules, in order to better understand at a molecular level the role of these OH sites on the hydrophilic properties of graphite surface modelling soot emitted by aircraft. (c) 2005 Elsevier B.V. All rights reserved.