Nanoparticles: Characterization and exposure metrics

Abstract: Exposure to aerosol nanoparticles has always been present in the evolution of humans, and thus has the human body developed ways of dealing with particles that enters the body. However with the emerging nanotech industry, new types of nanoparticles are being produced and used. Many of these particles have properties never seen before and this rise concern about how exposure to them might cause unwanted health effects. The research field of occupational health tends to move slower than the field of materials research. This is apparent when it comes to nanomaterials. The old exposure metrics based on mass is most likely not the best one to use for new materials such as carbon nanotubes (CNTs). In most applications only a few percent would be expected to be nanomaterials and the mass based methods often not that specific. Standards which rely on conventional optical microscopy have severe limits in resolution and won't be of any use when trying to detect, for example, release of single strands of CNTs. To get a better understanding of the possible adverse health effects of nanoparticle it is necessary to investigate a simpler system to isolate the importance of different factors, such as surface area. Understanding of the fundamental processes responsible of the outcome from aerosol processes generating these model particles need to be well understood to get the full picture of the model particles. In this thesis, work that aims to improve the understanding of exposure to nanomaterials is presented. Electron microscopy has been used in a systematic manner to detect nanomaterial, and a novel way of quantifying the detected material has been developed. Synergistic combinations of measurement methods from field measurements are shown, and methods for characterization of model particles are presented.