There is no biological history of mass masking until the current era. It is important to consider possible outcomes of this society-wide experiment. The consequences to the health of individuals is as yet unknown.
Masked individuals have measurably higher inspiratory flow than non-masked individuals. This study is of new masks removed from manufacturer packaging, as well as a laundered cloth mask, examined microscopically. Loose particulate was seen on each type of mask. Also, tight and loose fibers were seen on each type of mask. If every foreign particle and every fiber in every facemask is always secure and not detachable by airflow, then there should be no risk of inhalation of such particles and fibers. However, if even a small portion of mask fibers is detachable by inspiratory airflow, or if there is debris in mask manufacture or packaging or handling, then there is the possibility of not only entry of foreign material to the airways, but also entry to deep lung tissue, and potential pathological consequences of foreign bodies in the lungs.