Respirable particles from cutting and grinding ceramic tiles: A Scanning Electron Microscopy investigation

The ceramic sector is one of the regulated industrial field where potentially hazardous particles-generating activities occur, e.g. during the installation of tiles. The concentration of airborne respirable crystalline silica released during these tasks is a standardized measure of workers’ exposure. However, there is a lack of knowledge about the physical and chemical characteristics of the emitted particles, whose comprehension could provide a wider understanding of silica toxicity, which could be relevant also for the general population. This study aims to provide a morpho-chemical characterization with scanning electron microscopy of the respirable particles generated during tiles processing activities, realized by simulating an occupational exposure worst-case scenario. An automated microscopy workflow based on image analysis with a trained deep learning algorithm was applied. The findings revealed that a consistent proportion of the respirable particles were smaller than 1 μm. Single-particles elemental analysis provided the identification of silica particles and permitted to distinguish them from particles composed of other ceramic phases. The practical observations of size, shape and surface topography of the respirable particles presented in this work could suggest that, once inhaled, in addition to targeting the lung, the dust generated by tiles cutting and grinding could have an impact also on other human body districts, where particles can potentially translocate because of their size. Future investigations could be addressed by evaluating the presence of silica in human tissues, in addition to lungs, and assessing the reactivity of the freshly cut surfaces of ceramic particles.