Fiber Classification and the Influence of Average Air Humidity

Abstract

The use of man-made vitreous fibers (MMVFs) as a substitute for asbestos in industrial and residential applications has raised the concerns of the potential hazards associated with inhalable aerosolized fibers. The complex movement of fiber makes it difficult to predict the pattern of fiber deposition in human airways from the behavior of spherical particles. Difficulties in producing monodisperse length fibers has been an obstacle to study fibrous particle deposition in the human respiratory system. To address this problem, a narrow length distribution of fibers was generated using dielectrophoretic classification. Dielectrophoresis is the motion of neutral matter in a nonuniform electric field due to an induced dipole moment. It is sensitive to the conductivity of the matter in the field. A fiber classifier has been used to study the influence of atmospheric humidity on the behavior of glass fibers. Glass fibers, as insulators, can not be classified by the dielectrophoretic classifier. However, our study shows that a humidity higher than 15% RH can change the conductivity of the glass fibers so as to permit their effective classification.