Fibrous materials, such as MMVFs (man-made vitreous fibers), are widely used in thermal and electrical insulation, weatherproofing, and filtration media. These materials can be released as airborne respirable particles during their production and use. Airborne asbestos and other fibers can cause lung diseases including asbestosis, fibrosis and lung cancer. Thus mass production and wide use of these materials have raised concern over the potential health hazard to production employees associated with inhalable aerosolized fibers.

Inhalation is the major route of exposure to mineral fibers that have been shown to cause lung disease in humans. The health effects of exposure to airborne fibers often more depend upon the region of the respiratory tract into which the particles can penetrate and deposit. Once the fibers have deposited, their acute or chronic effects depend on other additional effects. Fiber size and physical dimensions have significant effect on regional respiratory deposition.

The human nose filters, warms, and humidifies inspired air. It is the important first protective line that captures harmful particles and vapor pollutants, preventing them from reaching the more delicate structure of deep lung. Particle deposition in the human nose has been studied for many years. However, the compact size, complex geometry and dynamic feature of the nasal cavity have made the thorough experimental study of particle deposition challenging. Results of early studies were unsatisfactory and some of them provided conflicting results. For fibrous particle deposition, the situation is even less satisfactory: we do not have enough information from experimental studies. Although several studies of fibrous particle deposition in human nasal airway have been performed with human nasal casts, further experimental studies are necessary to include different kinds of particles and a variety of nasal models. So far, we do not have any proper empirical equations to predict fibrous particle deposition in human nose.

In this study, 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 was used to study the influence of atmosphere humidity on the behavior of glass fibers.

In this study, physical models of human nasal passages were developed from MRI files by using Gambit and AutoDesk. A stereolithography machine was used to construct the airway models. Glass fiber aerosol was generated by using an electrical fiber classifier and passed through these models. The deposition efficiencies of both spherical particles and glass fibers within nasal models were acquired, analyzed and reported. The influential factors and semi-empirical equations of prediction were also proposed and discussed. A method of estimation of pressure drop across a nasal model was also suggested. For the first time, this study provides a feasible method to predict the particle deposition (both spherical and fibrous) efficiency in a human nasal cavity.