It is well known that person-to-person transmission mechanisms of respiratory viruses is a difficult subject to investigate, because contagious viruses are “invisible” and in-person experiments are morally challenging. It is therefore left to circumstantial observations, and speculative inferences, to determine the best techniques and practical means to slow, or even prevent in some circumstances, the random and rapid spread of infectious pathogens.

With viruses that manifest in the respiratory system, a strong case can be made that a likely path for person-to-person infection is by breathing in airborne contaminants in the form of saliva and mucus aerosols that are naturally expelled with normal breathing. It is my opinion that the most important and logical proactive steps we can take to mitigate cross-contamination is to actively control air convection-currents, along with continuous HEPA filtering of the air in closed indoor PUBLIC spaces.