Monitoring multiwalled carbon nanotube exposure in carbon nanotube research facility.
With the increased production and widespread use of multiwalled carbon nanotubes (MWCNTs), human and environmental exposure to MWCNTs is inevitably increasing. Therefore, this study monitored the possible exposure to MWCNT release in a carbon nanotube research laboratory. To estimate the potential exposure of researchers and evaluate the improvement of the workplace environment after the implementation of protective control measures, personal and area monitoring were conducted in an MWCNT research facility where the researchers handled unrefined materials. The number, composition, and aspect ratio of MWCNTs were measured using scanning transmission electron microscopy with an energy-dispersive x-ray analyzer. The gravimetric concentrations of total dust before any control measures ranged from 0.21 to 0.43 mg/m(3), then decreased to a nondetectable level after implementing the control measures. The number of MWCNTs in the samples obtained from the MWCNT blending laboratory ranged from 172.9 to 193.6 MWCNTs/cc before the control measures, and decreased to 0.018-0.05 MWCNTs/cc after the protective improvements. The real-time monitoring of aerosol particles provided a signature of the MWCNTs released from the blending equipment in laboratory C. In particular, the number size response of an aerodynamic particle sizer with a relatively high concentration in the range of 2 to 3 microm in aerodynamic diameter revealed the evidence of MWCNT exposure. The black carbon mass concentration also increased significantly during the MWCNT release process. Therefore, the present study suggests that the conventional industrial hygiene measures can significantly reduce exposure to airborne MWCNTs and other particulate materials in a nano research facility.
Chemical Safety and Health Research Center, Daejeon, and College of Veterinary, Seoul National University, Seoul, Korea.
Jeong Hee
JH
Han
Eun Jung
EJ
Lee
Ji Hyun
JH
Lee
Kang Pyo
KP
So
Young Hee
YH
Lee
Gwi Nam
GN
Bae
Seung-Bok
SB
Lee
Jun Ho
JH
Ji
Myung Haing
MH
Cho
Il Je
IJ
Yu
D000336:Aerosols; D000395:Air Pollutants, Occupational / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000032:analysis*; D016273:Occupational Exposure / Q000032:analysis*; D010316:Particle Size; D012106:Research / Q000592:standards*; D013499:Surface Properties; D017132:Workplace / Q000592:standards*
D000336:Aerosols; D000395:Air Pollutants, Occupational; D037742:Nanotubes, Carbon