Common sense? Restricting exhalation to reduce transmission of airborne disease? Have you never been taught to cover your mouth when you sneeze or cough?
Like it would be remarkable if it did nothing. THAT would be a blockbuster result.
The thing worth studying is if the effect is worth the trouble or not. It could be worth doing or it could effectively be a waste of time due to whatever other factor.
Like it would be remarkable if it did nothing. THAT would be a blockbuster result.
The thing worth studying is if the effect is worth the trouble or not. It could be worth doing or it could effectively be a waste of time due to whatever other factor.