A DIY mask made from a common cotton t-shirt is approximately N70. This article breaks down the effectiveness and breathability of different materials. https:/

A DIY mask made from a common cotton t-shirt is approximately N70. This article breaks down the effectiveness and breathability of different materials. https://smartairfilters.com/en/blog/best-materials-make-diy-face-mask-virus/ https://smartairfilters.com/en/blog/best-materials-make-diy-...