Indoor pollutants can damage cultural property stored in museums, art galleries, libraries and archives. A relatively small number of measurements available for the interiors are restricted to just a few gases. The paper draws attention to the lack of information about the airborne pollutants＇ dispersion of museum interiors and presents a mathematical model, implemented in a general computer code, that can provide detailed information on velocity and temperature as well as pollutants＇ concentrations prevailing in three-dimensional buildings of any geometrical complexity, for given external meteorological conditions. The model involves the partial differential equations governing flow Brid heat transfer, in large enclosures, containing heat and pollutants sources. Turbulent flow is simulated and buoyancy effects are taken into-account. The model allows for such practical aspects of the problems under consideration as blockages, internal heat and contaminants loads, external weather conditions, the presence of people, etc. The model is used to assess the environmental conditions inside the main Hall of the National Archaeological Museum of Athens (Myceane Hall) with external conditions corresponding to Ministry of Environment summer and winter days. (C) 2000 Elsevier Science S.A. All rights reserved.