c_heat
2020-1-24 13:35:17
Respiratory droplets, all droplets generated by an expiratory event—coughing, sneezing, laughing, talking, breathing—have diameters d that cover a large size range from approximately 0.6 to more than 1000 µm”
飛沫最細去到0.6micron
BFE block to 1micron
當然係咪真係會中剩低個0.4係難講
but better buy PFE to cover that