Wearing a face mask can reduce the distance that aerosols and droplets travel when someone is speaking or coughing – possibly by half, a new study suggests.
The study, published Wednesday in The Journal of Infectious Diseases, adds to mounting evidence that shows face masks help limit the spread of the coronavirus that causes Covid-19, and other airborne respiratory pathogens too.
Researchers at the University of Central Florida in Orlando conducted the study, involving 14 participants ages 21 to 31. Each participant recited a phrase and simulated a cough for five minutes in three different scenarios: without wearing a mask, while wearing a single-layer cloth mask, and while wearing a three-layered disposable surgical mask. N95 and KN95 masks were not included in the study. The phrase participants recited was, "The quick brown fox jumps over the lazy dog into a field of pretty playful perpetually purple pandas."
The researchers used high-power illumination instruments to detect aerosols and droplets coming from the participants as they spoke and simulated coughs.
The researchers found that without face coverings, droplets and aerosols traveled up to about 4 feet when someone was speaking, and up to 4.5 feet when coughing. The cloth mask reduced those maximum distances to about 2 feet for speech and 2.2 feet when coughing, and disposable masks reduced the distances further to 0.50 feet for both scenarios, according to the study.
"This study quantified that face coverings exhibit different distribution and velocity characteristics in comparison to without a face covering for both cough and speech," the researchers wrote in part in the study. "All face covering types reduce expelled volume and propagation distance, with the disposable face covering being the most effective at reducing both."
The researchers added that their findings suggest practicing a physical distance of 3 feet while wearing a mask appears to be equally as effective as 6 feet of physical distancing without a mask.
The current US Centers for Disease Control and Prevention recommendation for social distancing is to stay 6 feet apart.