Exposure assessment of nano-CaCO_3 manufacturing workplaces

摘要

Eight nanosized CaCO_3 (nano-CaCO_3) manufacturing workplaces in a plant were investigated for the possible exposure to nanoparticles (NPs). Personal sampling, area sampling, and real-time monitoring were performed using CPC (condensation particle counter) and OPC (optical particle counter) to characterize the mass exposure, particle size distribution, and particle number exposure. Only the mass concentration for area samplings in package and waste treatment workplaces were found to exceed the PNOS (particles not otherwise specified; 3 mg/m~3) set by ACGIH (American Conference of Governmental Industrial Hygienists), but lower than the OELs (occupational exposure levels, 4.0 mg/m~3) set by the China Ministry of Health for CaCO_3 fine, other workplaces were relatively lower than existing occupational exposure limits. The NPs and fine particles were most frequently released in package and waste treatment workplaces lacking of the engineering control. The mass concentration for area sampling in waste treatment workplace reached their highest values at 3.2647 mg/m~3, while the number concentration in package workplace reached their highest values at 4.07×10~(11) pt/m~3. So the workplaces of package and recovering particles in nano-CaCO_3 handling progress were the major emission sources of NPs.