Other than the obvious that masks work and work better the more people wear them, this paper seems to highlight the important of speech for producing small particles that float longer. Breathing has more momentum to the particles but talking produces smaller particles that break up further.<p>I don't like that they suggest fit standards rated masks (ie, brand name N95) should be reserved exclusively for medical and related persons. That was okay a year ago but it's really time to increase production of tightly fit low pressure drop N95 masks for everyone.