Face masks have limited value in protection from air born virus. If they were perfect the compliance is low. If the material was perfect barrier there is leak all around many of them. If they were perfect there is a virus avenue via the eye, lacrimal duct to pharynx. If they were perfect the warmth and moisture from breathing makes them a perfect culture medium to collect virus and bacteria for proliferation and growth. Solutions are being sought.
https://www.fau.edu/newsdesk/articles/mask-sanitizer-technology.php
