I have been wearing N95 painter's masks purchased at Home Depot or Lowes on trans-Atlantic and trans-Pacific flights since the 1990s. I put on the mask once I get seated, and once we are in the air and I put the seat flat, I am asleep. I awaken on the descent, and the mask keeps my throat and nose from drying out or becoming sore.
Today's pandemic notwithstanding, I recommend masks just for increased respiratory comfort on the aircraft.