9. Bad: Knitted Masks
Though thicker than bandanas and neck gaiters, knitted masks aren’t the most effective face masks out there. The knit allows for pockets throughout the mask that air can flow through, and they don’t provide a sufficient seal in the sides of the mask.
8. Bad: Cotton T-Shirt Masks
The same material that makes t-shirts so comfortable to wear doesn’t function well as a barrier against droplets. T-shirts are often soft, airy, and breathable—all factors that work against them as material for a face mask. However, it’s not just the material of a face mask that matters; how many layers make up the mask is also a factor. In another study, when cotton t-shirt masks are doubled up, they can provide 98% droplet blocking efficiency along with excellent breathability.
7. Good: Fitted N95 Face Mask
Unless they work in healthcare or manufacturing, most people aren’t aware that an N95 face mask requires a fit test to work its best. A fit test determines the correct tight-fitting mask size for the wearer. However, even without a fit test, the N95 mask blocks droplets excellently (only 0.1% of droplets passed through in the Duke study). This is not a surprise because N95 masks are made to protect people from air particulates. Used most often in medical settings where there’s a high risk of infection, the N95 mask protects the wearer and the people around them.