The N95 has been shown to provide the most protection, because it filters out at least 95% of the articles in the air. But they’re mostly worn by healthcare workers, and they aren’t always easy to find (and they also feel the most stifling to wear). If an N95 isn’t available, the next best options are a surgical mask or a cloth mask that has multiple layers. That includes a homemade mask, especially if it’s made out of tightly-woven cotton. Whatever you wear, make sure it covers your nose and your mouth. There are masks you should avoid, though. Those include masks with an exhalation valve because of the potential for releasing unfiltered air into the environment, bandanas, and neck gaiters.