The latest study of face masks suggests some work very well, but others might do more harm than good.
The Duke University study tested 14 different types of masks -- everything from N95 masks, to homemade cotton masks, to neck tubes.
Researchers wanted to see how well each mask controlled the number of respiratory droplets transmitted through the material -- an indicator of how well they could control droplets that carry viral particles.
The group confirmed that polypropylene, surgical and N95 masks transmitted the fewest respiratory droplets during speech. Some accordion-type cotton masks did a good job controlling droplets as well.
Yet researchers raised red flags over bandanas and gaiter styles neck fleece - sometimes called "buffs." The study found these types of face coverings actually turned large droplets into smaller ones that could hang in the air longer and created more droplets than going without a mask at all.