Public health officials recommend that people wear non-medical, fabric masks in public places to help reduce the risk of COVID-19. That could help prevent an infected person from releasing droplets into the air and exposing others to the coronavirus.
Now, researchers found the material that offers the best protection and can be easily used for DIY face masks. Using two layers of quilting fabric appeared effective in preventing droplets from escaping the mask after a cough or sneeze.
The team from Florida Atlantic University tested different materials that have been widely used on non-medical masks amid the COVID-19 pandemic. They also analyzed how a loosely folded homemade face mask, a bandana-style face covering and a cone-style non-sterile commercial mask can provide protection.
“While there are a few prior studies on the effectiveness of medical-grade equipment, we don’t have a lot of information about the cloth-based coverings that are most accessible to us at present,” Siddhartha Verma, study author and an assistant professor at Florida Atlantic University, said, as quoted by CNN. “Our hope is that the visualizations presented in the paper help convey the rationale behind the recommendations for social distancing and using face masks.”
In the experiment, Verma and colleagues used a mannequin to emulate a person’s nasal passages. It was able to sneeze or cough through a manual pump and a smoke generator.
The findings, published in the journal Physics of Fluids, show droplets from an uncovered cough could travel more than 8 feet from the source. When wearing facial coverings, the distance significantly decreased.
With a bandana the droplets stayed airborne for up to 3 feet, while using a folded cotton handkerchief cut the distance it traveled to 1 foot, 3 inches. When wearing a cone-style mask from pharmacies the droplets traveled about 8 inches.
Stitched-quilting fabric masks showed the best result. The droplets traveled only 2.5 inches from the mannequin.
“We found that although the unobstructed turbulent jets were observed to travel up to 12 feet, a large majority of the ejected droplets fell to the ground by this point,” Manhar Dhanak, study co-author and a professor at Florida Atlantic University, said. “Importantly, both the number and concentration of the droplets will decrease with increasing distance, which is the fundamental rationale behind social-distancing.”
The researchers hope that the study will guide healthcare professionals, medical researchers and manufacturers in testing the effectiveness of other face masks.