Research Article
Three-Day Continuous Exposure Monitoring of CNT Manufacturing Workplaces
Ji Hyun Lee, Kang Ho Ahn, Sun Man Kim, Ellen Kim, Gun Ho Lee, Jeong Hee Han, Il Je Yu
Published:
DOI:
10.1155/2015/237140
License:
Copyright © 2015 Ji Hyun Lee et al.
2015
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Continuous monitoring for possible exposure to carbon nanotubes was conducted over a period of 2 to 3 days at workplaces that manufacture multiwall carbon nanotubes (MWCNTs) and single wall carbon nanotubes (SWCNTs). To estimate the potential emission of carbon nanotubes (CNTs) and potential exposure of workers, personal sampling, area monitoring, and real-time monitoring using an scanning mobility particle sizer (SMPS) and dust monitor were conducted at workplaces where the workers manufactured CNTs. The personal and area sampling of the total suspended particulate (TSP) at the MWCNT manufacturing facilities ranged from 0.031 to 0.254 and from N.D (not detected) to 0.253 mg/m3, respectively. This 2- to 3-day monitoring study found that nanoparticles were released when opening the chemical vapor deposit (CVD) reactor door after the synthesis of MWCNTs, when transferring the MWCNTs to containers and during blending and grinding. However, distinguishing the background concentration from the work process particle emission was complicated due to sustained and even increased particle concentrations after the work processes were terminated. The MWCNTs sampled for transmission electron microscopy (TEM) observation exhibited a tangled shape with no individual dispersed CNT structures.