Study: Face Masks Cut Distance Traveled by Airborne Pathogens in Half

Based on the results, the investigators found that a cloth face covering reduced emissions in all directions to about 2 feet compared to the 4 feet of emissions produced when coughing or speaking with no mask on.

A new study from the University of Central Florida (UCF) found that face masks reduce the distance airborne pathogens could travel--specifically when speaking or coughing--by more than half compared to not wearing a mask.

Knowing how to reduce this kind of transmission distance can help keep people safe and aid in managing responses to pandemics, which could allow for more relaxed social distancing guidelines when masks are worn.

“The research provides clear evidence and guidelines that 3 feet of distancing with face coverings is better than 6 feet of distancing without face coverings,” said study co-author Kareem Ahmed, associate professor in UCF’s Department of Mechanical and Aerospace Engineering, in the press release.

The research team used diagnostic tools to measure the distance in all directions that droplets and aerosols travel from people speaking and coughing when they wear different types of masks and when they do not. A total of 14 people participated in the study, with 11 males and 3 females between 21 and 31 years of age.

During the study, investigators asked each participant to recite a phrase and simulate a cough for 5 minutes without a face-covering. Following this, participants would then repeat this task with a cloth face covering and then also with a 3-layered disposable surgical mask. The team used planar particle imaging to measure particle velocity, a phase doppler interferometer to measure droplet size, velocity and volume flux at points within a spray plume, and an aerodynamic particle sizer to determine airborne particle behavior, according to the study authors.

Based on the results, the investigators found that a cloth face covering reduced emissions in all directions to about 2 feet compared to the 4 feet of emissions produced when coughing or speaking with no mask on. Additionally, the reduction was even greater when wearing a surgical mask, which reduced the distance that coughing and speaking emissions traveled to approximately half a foot.

Additionally, the investigators noted that in the future they plan to increase the study cohort size to continue to assess effective methods of managing airborne disease transmission.

REFERENCE

Face masks cut distance airborne pathogens could travel in half, new study finds. EurekAlert! January 12, 2022. Accessed January 12, 2022. https://www.eurekalert.org/news-releases/939703