| Summary: | This thesis has been completed at the Department of Applied Physics and Mechanical Engineering at Luleå University of Technology in Luleå, Sweden and at the School of Mathematical Sciences at Monash University in Melbourne, Australia. The research has been carried out at CSIRO Commonwealth Scientific and Industrial Research Organisation) Marine and Atmospheric Research in Aspendale, Australia. Aerosols are defined as suspensions of solid or liquid particles in a gas. Atmospheric aerosol particles have been shown to affect climate, visibility and human health. In particular, particle mass concentrations and size distributions are of crucial importance to the aerosol's impact on human health. These properties are therefore routinely measured by regulatory authorities in many countries. However, the process of removing aerosol from the atmosphere during the measurement or sampling inherently results in some modification of the aerosol. The aim of this project is to determine the volatility of urban aerosol as a function of particle size and to investigate the effect of aerosol pre-treatment during sampling and measurement. The study suggests that aerosol mass loss depends on particle size, temperature and time. Fine particles with diameter smaller than 2.5 micrometres are more volatile than coarse particles with diameter larger than 2.5 micrometres. Most mass is lost from fine particles with a diameter around 1 micrometres and the mass loss of the fine particles increases as a function of temperature and time. Coarse particles are not affected by changes in heating temperature and the mass loss is restricted to the first hour of heating. These observations can be explained by the predominance of volatile material in fine particles while coarse particles are mainly composed of refractive non-volatile material and are in general relatively inert chemically. Validerat; 20101217 (root)
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