[Airborne particles in a multi-wall carbon nanotube production plant: observation of particle emission and personal exposure 1: Measurement in the packing process].
OBJECTIVE
In order to assess the exposure risks of multiwall carbon nanotubes (MWCNT) for packing workers, we carried out real-time monitoring in the two types of packing facilities of MWCNT, and exposure measurements for the packing workers.


METHODS
In the real-time monitoring, a scanning mobility particle sizer (SMPS) and an optical particle counter (OPC) were used to measure nanoscale particles and sub-micron/micron scale particles, respectively. A personal sampler with PM 4.0 was used to measure the personal exposures in the packing facilities.


RESULTS
One of the packing facilities is manually operated and the other is automated. The concentrations of airborne dust in both facilities were almost the same as each other at 0.24 mg/m(3) (total dust). However, the results of personal exposure measurements were quite different between the two facilities. The exposure concentrations of workers in the manually and automated operations were 2.39/0.39 (total/respirable) mg/m(3) and 0.29/0.08 (total/respirable) mg/m(3), respectively. From the time series study, submicron scale particles were released into the workplace air when the CNT products were put into temporary container bags from a hopper and manually packed into shipping bags. However, the task-related nanoscale particle release was not observed.


CONCLUSIONS
The manual packing operation is one of the "hot spots" in MWCNT production facilities, and automation brings much improvement to reduce MWCNT exposure.
Working Environment Research Group, National Institute of Occupational Safety and Health, 6-21-1 Nagao, Tama-ku, Kawasaki 214-8585, Japan.
Mitsutoshi
M
Takaya
Fumio
F
Serita
Mariko
M
Ono-Ogasawara
Yasushi
Y
Shinohara
Hiroyuki
H
Saito
Shigeki
S
Koda
D000395:Air Pollutants, Occupational / Q000032:analysis*; D001331:Automation; D003199:Computer Systems; D004784:Environmental Monitoring; D053758:Nanoparticles / Q000032:analysis*; D037742:Nanotubes, Carbon / Q000032:analysis*
D000395:Air Pollutants, Occupational; D037742:Nanotubes, Carbon