I’ve been testing out more than a dozen different options from different outdoor brands over the past month or so. Favorite Overall: Outdoor Research Essential Face Mask ($20)Another mask with a filter pocket, the OR mask is a terrific blend of comfort, stability, breathability, and moisture-wicking. The filter pocket is prone to scrunching the included filters, but that’s the only gripe. Best for Demanding Physical Activities: Buff Filter Mask ($29)This mask boasts the sheerest and lightest feel, though it’s a double layer of polyester for extra protection. It also has a filter pocket and the mask comes with a handful of thin filters.