COVID. As I said in an earlier post, the idjits walking around with N95s or the N95 wannabee's (masks with valves) are doing more harm than good. And, if you are a "gaiter" wearer, you should just go without a mask as well. Keep on following the "science".
Link: https://www.washingtonpost.com/health/2020/08/13/cdc-mask-guidance-masks-valves/