Size distributions and exposure concentrations of nanoparticles associated with the emissions of oil mists from fastener manufacturing processes

► A developed MEAD was used to characterize workers' exposure of oil mist nanoparticle. ► The size distributions of nanoparticles were consistently in the form of uni-modal. ► A difference of nanoparticle exposure was found while different metrics were used. ► The MEAD results are suitable for assessing oil mist nanoparticle exposures.