If the evaluations failed to reveal significant concentrations of NP in three research laboratories, it is different for the other workplaces. Thus, high concentrations of PUF were measured in the aluminium smelter, especially near the furnaces. For their part, the apprentice welders were mainly exposed to peak concentrations of particles in both schools. Among the six welding processes studied, the highest concentrations were generated by flame cutting when aluminum was used. As for the workers of the factory processing thermoplastic materials, they were exposed to high levels of carbon nanoparticles in storage rooms and transformation, particularly in the operation of the extruder.
This study is the result of a call for proposals launched jointly by the Institut de recherche Robert-Sauvé Occupational Health and Safety (IRSST) and NanoQuébec. To accomplish this, the researchers evaluated concentrations using digital particle counters (P-Track, model 8525) and used a low-pressure impactor electrical detection (ELPI) to measure the size of NM. Although there is no consensus on evaluation measures, the study shows that the P-Track is a tool well suited to assess concentrations of PUF while residing several uncertainties in assessing exposure to NP. The field studies should include an assessment of the distribution of particle size to confirm their presence.
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