How far away were the petri dishes? The original paper does not say. If they are one foot away, it's no surprise they got infected.
A mask can probably stop a 100 mph sneeze from sending aerosols 30 feet. Maybe they attenuate the sneeze and limit the trajectory and distance to 2 or 3 feet. If so, that would be valuable.
This strikes me as not very useful research. They should have put petri dishes at 1 foot intervals to 6 feet, then 2 foot intervals the next 6 feet, then 5 foot intervals out to 30 feet.
Petri dish was 20 cm away. That’s less than 8 inches.
Masks lowered the viral load even at that distance.
This strikes me as not very useful research.