I am surprised and disappointed that there is a need to wear face masks in Korea to protect one from the pollution. Some days the air is thick with something - it looks and feels like some weird haze. It is common for people to wear face masks. Surprisingly many people wear them - from cute fabric masks that cover the nose and mouth, to full face masks of paper.
As well it is common to see people wearing sun visors - but with a longer "beak" that many sun visors and often they are pulled over the face - so the wearer looks like some visitor from outer space.