Masks Work & How To Make Your Own Face Masks

They blocked the flow of the droplets in the tube with five different types of mask materials -- a regular cloth mask, a two-layer cloth mask, a wet two-layer cloth mask, a surgical mask, and a medical-grade N-95 mask.

Each of the masks captured the vast majority of droplets, ranging from the regular cloth mask, which allowed about 3.6% of the droplets to go through, to the N-95 mask, which statistically stopped 100% of the droplets. But at distances of less than 6 feet, even those small percentages of droplets can be enough to get someone sick, especially if a person with COVID-19 sneezes or coughs multiple times

New research shows effectiveness of masks at stopping droplets. At distances under 6ft, the small % of droplets that aren’t stopped (and the ones that are aerosolised) could be enough to get someone sick.

https://www.eurekalert.org/pub_releases/2020-12/aiop-mne122120.php