Public health experts and doctors agree everyone needs to wear a facial covering to help prevent the spread of coronavirus. However, a new study out of Duke University shows not all facial coverings are equally effective. Some very popular ones could actually do more harm than good.
Researchers used a box, laser, lens and cell phone camera to visualize droplets and filmed someone speaking into the box.
The study found that facial coverings like N95 masks without valves were the most effective. Surgical masks came in second. Masks made with polypropylene were next, then cotton-pleated masks with two layers, then one layer.
Bandana and neck gaiters came in last. The study found they not only performed the worst, they potentially could do more harm than good.
Researchers say the big particles were broken up into smaller particles - which may hang in the air longer.
"Yes, there is evidence that the virus travels through smaller droplets, [but] is it infectious? Is it enough to cause infection? It's still a question based on the guidance by the World Health Organization and by the CDC," said Dr. Abisola Olulade of Sharp Rees-Stealy.
She said the study should be interpreted with caution. However, she points out more layers tend to be better than fewer layers, and gaiters are typically thin.
"If the fabric is more stretchy, if it's thin, which is what most neck gaiters tend to be, then you may not be getting enough protection from it," she said.
The bottom line, she said, "It is important to wear masks. I don't want anyone to read the study and get confused and say they're not effective, they are effective."
Even though N95 masks and surgical masks are the most effective, experts say they're not necessary for everyday life.