An experiment published in the New England Journal of Medicine demonstrates how a damp cloth over someone’s mouth can reduce the number of speech-generated droplets propelled into the air.
The visualization, which was published Wednesday, comes amid increased interest in the impact of the airborne droplets as it relates to the spread of COVID-19.
The experiment used laser light-scattering to show the trajectory of speech-generated droplets, both with and without a person’s mouth covered.
Damp face coverings were demonstrated to be effective in reducing the number of forward-moving droplets, and the loudness of speech — the louder the person spoke, the more droplets were emitted — also had an impact on the number of droplets.
The study also said some studies have shown speech can produce the same number of droplets as coughing.
View the full letter and the video using light-scattering here.
