In machine workshops and laboratories, specific materials and chemicals are processed and toxic aerosols may be released into air. For protection of the health of employees working in that environment, it is therefore important to gather knowledge about aerosol composition related to specific working activity and to monitor the aerosol concentration levels. An extensive study of this kind was performed in the machine workshop of Jožef Stefan Institute using a combination of time-, particle size- and location-resolved sampling. The majority of samples were analyzed by particle induced X-ray emission (PIXE) and energy dispersive X-ray spectrometry (EDX) techniques and the main results have been described in a separate paper. Here, we concentrate on presenting the results of individual particle analysis of an aerosol emission that is related to a short, unexpected episode related to the restoration of old furniture. Although the activity was identified by a strong correlation of elemental concentrations in a series of samples taken with a 2-h time resolution, the single microparticle analysis of the cascade impactor samples taken over the longer time period offered an additional insight into the corresponding aerosol composition. The analysis of the aerosol size-selected samples revealed strong pair correlations among concentration levels of Ba, Zn, S, Pb and Cl in a number of individual microparticles. The result is explained by the emission of Ba- and Pb-rich aerosol particles in course of removal of the old white paint layers. The former particles appear to originate from white pigment called lithopone, which is a mixture of BaSO4 and ZnS, and the latter group seems to be related to Pattinson's white lead PbCl·OH. Although the individual particle analysis by itself is in principle capable of assigning the emission source, in this case, it was used as an excellent tool to enhance the quality of source characterization.
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