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 TiO(2), 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.

The effects found in both mines indicate that the mixed exposure can cause lung function disorders in salt miners exposed over a long time. Because of the high correlation of the concentrations it was not possible to determine the effects of a single exposure component separately or to recommend a specific occupational exposure limit. However, possible maximum effects associated with the mixed exposure can be evaluated in the ranges of concentrations of the individual substances in the mines.

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Significant differences between non-smokers and active smokers were found for most of the leukocyte types (e.g. granulocytes P = 0.000, lymphocytes P = 0.002, T-cells P = 0.033) and for some soluble parameters (ICAM P = 0.000, IgM P = 0.007, IgE P = 0.035). Increasing numbers of total lymphocytes, T-cells and HLA-DR positive T-cells in relation to exposure were found by linear regression analysis (e.g. for inhalable dust:total lymphocytes P = 0.011, T-cells P = 0.061, HLA-DR positive T-cells P = 0.007). CONCLUSION. Comparison of immunological markers in non-smokers and active smokers confirms leukocytosis and inflammation following tobacco consumption. The combined exposure of salt dust, diesel exhaust and NOx seems to influence the immune system. Together, the results suggest that the analysis of leukocytes and their subsets can complete other investigations (lung function, questionnaire) to monitor exposure-response relationships in occupational studies investigating the effect of inhaled substances. Longitudinal studies will be necessary to determine the predictive value of the immunological changes.

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