You cant have a combination - the particle is either hyperbaric or hypobaric. However as I said above, I do not think the issue is so simple - my conclusion is that masks are not a clearcut benefit, NPIs taken as a whole are. Data must be considered carefully - the CDC reference you provide does advise covering the face to sneeze...and staying at home. I am a sort of scientist, not a politician so I can say I dont know
