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Workplace exposure to engineered nanoparticles

Measurement strategies as well as results from measurements at workplaces are presented. Measurements were performed in research laboratories as well as by companies producing small amounts of nanostructured materials. The work was done in the frame of a BAuA (Bundesanstalt für Arbeitsschutz und Arbeitsmedizin) research project. Measurement results during manufacturing and processing of TiO2, nanofibers as well as synthetic ceramic nanopowders and nanostructured materials used for the electrical industry are demonstrated. Measurements were conducted with a scanning mobility particle sizer (Grimm) and a concentration particle counter (TSI). Mean number concentrations of nanoparticles are presented. During determination of particle number concentrations, a distinction must be drawn between the particle number in the ambient air and the particle number resulting from work processes. Thus a special measurement strategy was developed including measurement of the ambient air and also analysis by electron microscopy to define the size of agglomerates as well as the data related to the chemical composition. To date, no significant increase of nanoparticle number has been found provided proper handling was guaranteed (e.g., closed systems, extractor hood). Nevertheless, a few particle agglomerates of the materials used during the work process, as shown by electron microscopy, were detected. Probably nanostructured materials can primarily be released during cleaning and maintenance operations as well as in the case of a failure of normal operation.