Pedestrians in Japan wearing surgical masks on Feb. 4, 2020. (Credit: Rodrigo Reyes Marin/Shutterstock)Sign up for our email newsletter for the latest science news1 free article leftWant More? Get unlimited access for as low as $1.99/monthAlready a subscriber? or Want more?Keep reading for as low as $1.99!Already a subscriber? or Related ContentStay CuriousJoinOur ListSign up for our weekly science updates.SubscribeTo The MagazineSave up to the cover price when you subscribe to Discover magazine.…Pedestrians in Japan wearing surgical masks on Feb. 4, 2020. (Credit: Rodrigo Reyes Marin/Shutterstock)Sign up for our email newsletter for the latest science news1 free article leftWant More? Get unlimited access for as low as $1.99/monthAlready a subscriber? or Want more?Keep reading for as low as $1.99!Already a subscriber? or Related ContentStay CuriousJoinOur ListSign up for our weekly science updates.SubscribeTo The MagazineSave up to the cover price when you subscribe to Discover magazine.WW…