In this study, the authors undertook nanoparticle (NP, diameter < 100 nm) and respirable particles measurements at three different nanopowder workplaces, including the mixing area of a nano-SiO2-epoxy moulding compound plant (primary diameter: 15 nm), bagging areas of a nano-carbon black (nano-CB) (primary diameter: 32 nm) and a nano-CaCO3 (primary diameter: 94 nm) manufacturing plant. Chemical analysis of respirable particle mass (RPM) and NPs was performed to quantify the content of manufactured nanoparticles in the collected samples. Nanopowder products obtained from the plants were used in the laboratory dustiness testing using a rotating drum tester to obtain particle mass and number distributions. The obtained laboratory data was then used to elucidate the field data. Both field and laboratory data demonstrated that NP number and mass concentrations of manufactured materials were close to the background level. Number concentration was elevated only for particles with the electrical mobility diameter >100 nm during bagging or feeding processes, unless there were combustion-related incidental sources existed. Large fraction of nanomaterials was found in the RPM due to agglomeration of nanomaterials or attachment of nanomaterials to the larger particles. The authors concluded that RPM concentration measurements are necessary for the exposure assessment of nanoparticles in workplaces.
Authors: Tsai, Chuen-Jinn; Huang, Cheng-Yu; Chen, Sheng-Chieh; Ho, Chi-En; Huang, Cheng-Hsiung; Chen, Chun-Wan; Chang, Cheng-Ping; Tsai, Su-Jung; Ellenbecker, Michael J. ;Full Source: Journal of Nanoparticle Research [online computer file] 2011, 13(9), 4161-4172 (Eng) ;