The scientific rationale for the use of simple masks or improvised face coverings to trap exhaled aerosols and possibly reduce the breathborne spread of COVID-19.

The medical community agrees that breathborne infectious materials can be spread with exhaled aerosols and that asymptomatic people, i.e., those showing no symptoms, could be unknowingly infectious. With the current worldwide pandemic of the respiratory coronavirus disease 2019 (COVID-19), various health bodies and governments are recommending that the population wear some form of mask or improvised facial covers while out in public in an effort to reduce the spread of disease . The general concept is that more accessible masks or mask-like materials (scarves, bandanas, etc.) could serve to reduce the amount of infectious aerosol from infected people, and reduce the viral load in the environment. This editorial addresses the underlying scientific rationale that such inexpensive or improvised could indeed serve to reduce the emissions of infectious aerosol by the mechanism of surface adhesion and particle kinetics in addition to the filtration effect.