Characterisation of aerosol individual particles in a controlled underground area

The aim of this study is to determine the sources and provide a physico-che mical description of the airborne particulate present in two communicating underground areas: a highway tunnel with heavy vehicular traffic and a cont rolled underground laboratory. Individual particles were collected in the t wo zones and examined using scanning electron microscopy with EDS X-ray att achment. The principal components of the particulate were analysed using pr incipal factor analysis and hierarchical cluster analysis. The data obtaine d suggest that three main Factors determine airborne particulate pollution in the laboratory: the ventilation system for air replacement, the access o f motor vehicles into the laboratory, and the metallic installations and st ructure of the laboratory itself. (C) 1999 Elsevier Science Ltd. All rights reserved.