Physical changes of indoor dust caused by hot surface contact

The aim of this study was to achieve a better understanding of the physical changes of indoor dust as a result of heating. Indoor dust was collected f rom an office building, and the fine fraction was heated in the temperature range 50-250 degreesC. Characterisation of the dust was performed before a nd after contact with hot surface with respect to particle size and shape ( electron microscope), specific surface area (nitrogen adsorption method), n umber of particles (optical particle counting, condensation nucleus countin g) and weight loss (thermogravimetric analysis). Heat treatment induces a s ignificant increase in the number of emitted sub-micron particles, probably dominated by condensation particles. This occurs even at low temperatures, (50-100 degreesC), which are often present in an indoor environment. Size, shape and specific surface area of the residual dust show only minor diffe rences from non-heated dust. Emitted volatile organic compounds from the sa me experiments have been reported in a previous study and biological effect s are currently being studied. (C) 2001 Elsevier Science Ltd. All rights re served.