How to make or buy a covid-19 face mask that actually works

Your mask should cover your nose and mouth and should have fastenings that keep it firmly in place while you talk, move, and breathe. If you have to touch your face to adjust your mask, you risk exposing your nose or mouth to germs.

Ideally, the mask should have some kind of adjustable band to minimize gaps between your nose and your cheeks.

The most effective fabrics are water-resistant and tightly-woven—not stretchy or sheer. A tightly-woven cotton is the next best thing, and your mask should have at least two layers of it.