Friction associated with wear, representing non-combustion processes in traffic can pose a problem for the human health, mainly in terms of exposure to solid particles. During braking, substantial amounts of micron and sub-micron metal based particles are released into the environment. The aim of this pilot study was to evaluate whether these particles could reach the human body via respiratory exposure even when respiratory protective equipment is used. In this study, workers were exposed to resuspended dust particles for one hour during automotive brake dynamometer maintenance (particle removal and machine cleaning). The particles deposited in the dynamometer were generated during the laboratory tests of the friction performance of brakes using different types of friction composites. Throughout the course of the work, workers wore respiratory protective equipment to prevent particulates from entering the respiratory tract. These protective devices are being used in accordance with EN 140:1998 guidelines for protection against fine dust, water and oil-based liquid aerosols, viruses, bacteria, spores, organic and acid gases, vapors and ozone. A sample of saliva for the detection of trapped particles was analysed using scanning electron microscopy and Raman microspectroscopy. Quantification of these captured particles was performed by inductively coupled plasma atomic emission spectrometer and inductively coupled plasma mass spectrometer. The results show that in the saliva of the workers, particles/agglomerates of metal particles in micron and submicron dimensions were present, with the majority of Al, Fe, Ba, Zn, Cu, Sn, and Bi, which were present in the saliva of the workers even after an hour from the exposure to the wear particles despite wearing respiratory protective equipment.Keywords: respiratory protective equipment, metal based particles, Raman microspectroscopy, scanning electron microscopy, atomic emission spectrometry
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