Researchers have done a study and found that wearing one mask surgical or cloth mask - blocked around 40% of the particles in the air coming towards the head hat When we use a cloth mask worn on top of a surgical mask, about 80% were blocked when inhaling and exhaling. When double-masked, more than 95% of the particles in the air were blocked, says CDC's Dr. John Brooks. So It's safe to safe that we should double up for safety. Those that have breathing issues should always consult with their physician first! Stay safe out there and wear your mask.