Wearing bandanas or neck gaiters as face coverings to protect against COVID-19 may actually do more harm than not wearing a mask at all, a study published in Science Advances found.
Researchers at Durham, N.C.-based Duke University analyzed the effectiveness of 14 face coverings ranging from bandanas to N95 masks. They created a simple device involving a laser and cellphone camera to track individual particles emitted from a person's mouth when speaking. Researchers had trial participants say the same phrase with and without wearing each mask 10 times.
N95 masks proved the most effective, allowing no droplets to escape. Handmade cotton masks were about as effective as surgical masks, both blocking a substantial amount of droplets. Bandanas and breathable neck gaiters ranked least effective, emitting a higher droplet count than control tests involving no masks.
Bandanas and neck gaiters have more porous fabric, which may break up bigger particles into smaller ones that are more likely to float in the air, hence the higher droplet count, Martin Fischer, PhD, a chemist and physicist who developed the testing device, explained in a video created by Duke and cited by The Washington Post.
Dr. Fischer said these types of coverings are a popular choice among Americans because they are convenient to wear and don't restrict air, which is also why they're not offering much protection.
"It's not the case that any mask is better than nothing," he said in the video. "There are some masks that actually hurt rather than do good."
To view the full study, click here.