Occupational Exposure Assessment of CaCO3 Nanoparticles Using a Multi-Metrics Approach

The possible exposure to nanoparticles (NPs) were investigated in a nanosized CaCO3 manufacturing plant using a multi-metrics approach: mass concentration, number concentration, surface area (SA) concentration. The mass concentrations of particle ranged from 0.1497 to 3.2647 mg/m3 for area samplings. The SA concentrations of particles ranged from 149 to 3007μm2/cm3. The number concentrations of particle ranged from 3.56×1010 to 4.07×1011 pt/m3. The particle SA concentrations exhibited the same trend as the number concentrations, and the variability of these two exposure metrics between the eight areas was greater than the mass concentration. This indicates that occupational exposure assessments using mass concentration of NPs maybe underestimate their toxicity. The number concentrations had better linear relationship with SA concentrations versus mass concentrations (coefficients of correlation, R=0.84 and 0.75, respectively), and the mass concentrations had weakest linear relationship with SA concentrations (R=0.61). The surface area and number metrics may be a more suitable metric for NPs occupational exposure.