Asbestos fibers are very small in diameter and when airborne, it could take up from 13 minutes to 8 hour to settle down on one place. The smallest measurement for asbestos fiber is 0.5 micrometer and that would take at least 8 hour to settle if airborne.  Inhaling asbestos fibers will cause serious injuries which could lead to mesothelioma, malignant lung cancer or asbestos lung disease and also asbestosis, which is a type of pneumoconiosis.