Mask Filtration

There is a fundamental trade-off between filtration effectiveness and breathability: higher filtration means less air passes through. A four-layer 100% cotton bandana provides approximately 19.5% filtration, the lowest practical option. The standard benchmark filtration target is 0.3 microns, corresponding to N95 mask performance at 95% filtration. Individual viral particles at approximately 0.1 microns can theoretically pass through even the best standard masks, as they are three times smaller than the N95 pore size.