Exposure of engineered nano-sized and respirable particles at different workplaces

• Main Authors: Huang, Cheng-Yu, 黃政毓
• Other Authors: Tsai, Chuen-Jinn
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/82059890478393274419

碩士 === 國立交通大學 === 環境工程系所 === 99 === In this study, engineered nanoparticle (ENP) and respirable particles exposure measurements were conducted at three different ENP-related workplaces, including the mixing area of nano-SiO2 epoxy molding compound plant, two bagging areas of the nano-CaCO3 and nano-carbon black (nano-CB) manufacturing plants. Results show that NP mass concentration at the nano-CB manufacturing plant was the highest due to diesel forklift exhaust. The highest respirable particle mass (RPM) concentration was observed to be 1591±1051 ?慊/m3 at the nano-SiO2 epoxy molding compound plant, which was much higher than 159±52 and 154±74?n?慊/m3 at the bagging areas of the nano-CB and nano-CaCO3, respectively, due to higher NP emission rate and ineffective ventilation system at this location. The mass median aerodynamic diameters (MMADs) at these workplaces were supermicron rather than nano-sized, which was also confirmed by chemical analysis of the collected particles and the results of the rotating drum testing. The NP number concentration maintained at background level unless there were material handling activities or if the diesel forklifts were used in the workplaces. The TEM analysis showed that nano-sized particles indeed existed. However both the field exposure data and results of rotation drum test showed that although nanoparticle concentration was much higher than that of supermicron particles, its mass concentration was much lower due to agglomeration of nanoparticle into micron-sized particles. Therefore, it is suggested that both number and mass concentrations of nano-sized and respirable particles be considered when assessing the exposure of nanopowder-related workplaces.