Friday, August 14, 2009

Pilot Plant Data on Nanoparticle Exposure Shows a Significant Hazard

free full text. 188 ug/m^3 is a surprisingly high and concerning exposure level. The ACGIH recommends 25 ug for silica - are these more or less potent?

Exposure to Manufactured Nanostructured Particles
in an Industrial Pilot Plant
ETH Zurich, Institute of Environmental Engineering, Schafmattstrasse 6, 8093, Zurich, Switzerland
Received 7 February 2008; in final form 27 July 2008; published online 17 October 2008
Objectives: Nanomaterial production and the number of people directly in contact with these
materials are increasing. Yet, little is known on the association between exposure and corresponding
risks, such as pulmonary inflammation and oxidative stress.
Methods: Condensation Particle Counters, a DustTrak
and Scanning Mobility Particle
quantified real-time size, mass and number concentrations in a nanostructure particle
pilot-scale production facility, using a high-temperature gas-phase process, over a 25-day period.
Temporal and spatial analysis of particle concentrations and sizes was performed during
production, maintenance and handling. Number-based particle retention of breathing mask filters
used under real-time production and exposure conditions in the workplace was quantified.
Results: The results demonstrate elevated number concentrations during production, which
can be an order of magnitude higher than background levels. Average concentrations during
production were 59 100 cm
23 and 0.188 mg m23 for submicron particles. Mask filters decreased
particle number concentrations by
Conclusions: This study demonstrates real-time worker exposure during gas-phase nanoparticle
manufacturing. Qualitative and quantitative analysis of emission sources and concentration
levels in a production plant is accomplished. These results are important for workers,
employers and regulators in the nanotechnology field as they provide information on encountered
exposures and possibilities for mitigation measures.

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