Generation of size-selected fibers for a nose-only inhalation toxicity study

Abstract

A fiber length classifier based on dielectrophoretic separation of fibers was used develop a generator to evaluate the contribution of fiber length to the induction of lung disease. The fibers used in these experiments were glass fibers. They were prepared using a compression grinding technique and dry mixed with glass beads. The mixture was fed slowly into a new type of generator that used a high energy fluidization combined with a small dead volume to efficiently generate a stable aerosol with a concentration as high as 200 mg/m 3. The fibrous aerosol was selected in such a way as to only allow fibers shorter than a selected length to pass through the fiber length classifier. Exposure of the rats to this aerosol could be compared with exposure to the distribution without classification that included the long fibers. Previous work has indicated that fibers longer than the macrophage diameter (- 1/413 - 1/4m for rats) would cause a significant increase in toxicity. After passing through the classifier, a glass fiber concentration as high as 70 mg/m3 at 10 l/min may be available for exposure of the rats.