NEW ORLEANS — We’ve been hearing the plea to “Mask Up Louisiana” for months now. It’s one thing we all can do to slow the spread of the Coronavirus.
But not all masks are created equal.
A team of researchers at Duke University studied the effectiveness of 14 different types of face masks in filtering respiratory droplets. The Coronavirus is transmitted through those tiny particles when an infected person coughs, sneezes or talks.
Researchers used a laser beam and cellphone camera to show droplets in the air as people spoke.
“We had speakers say ‘stay healthy people’ without the mask and we used that as a baseline and we then put different masks on and visualized the effects of that mask that should reduce droplet emissions when you speak,” Duke chemist and physicist Martin Fischer, Ph.D. said.
Fischer said the research showed the best face coverings were N95 masks, the hospital-grade coverings used by health care workers. It led to a droplet transmission of below 0.1%.
Handmade cotton and polypropylene masks, some of which were made from apron material, also proved effective, with droplet transmission ranging from 0.1 to 0.4%.
None of the masks compared with the neck fleece, which had 110% droplet transmission. Researchers found the neck fleece actually increased the number of droplets by creating smaller particles from larger ones.
LSU Health Infectious Disease Specialist Dr. Fred Lopez said this style of face covering may be worse than wearing no mask at all.
“Larger droplets tend to drop to the ground, but if you have smaller droplets, they can stay airborne and can increase the risk for transmission,” Lopez said.
The Duke study also showed bandannas didn’t perform too well either, although it didn’t increase the transmission rate as the neck fleece did.
According to Dr. Lopez the bottom line takeaway from the study: Choose your mask wisely.
“I think there are better masks than the neck fleece,” Lopez said. “There are better masks than the bandannas. We should try to use those masks that prove to be more effective at decreasing droplet transmission.”
Dr. Fischer at Duke agrees.
“We certainly encourage everyone to wear a mask,” Fisher said. “But we want to make sure when you wear a mask and you go through the trouble of making a mask you make one or wear one that actually helps, not just you, but helps everyone.”
Remember, for any mask to be effective, make sure it fits over your nose and mouth, under your chin and snugly against both sides of your face.