I think most people assume that the facemasks are because they are afraid of getting sick or SARS or something like this. But it is actually the opposite, I suppose! They wear the masks because they are being considerate and worried about getting their germs on other people. I'd guess that anywhere from 25-50% of the people in subways and public areas of Japan wear these facemasks. I think they are actually kind of cool. It makes people very mysterious and you can just look at the eyes.
By the way, all of these were taken last week with the Sony A7r and the Leica 50mm f/1.4. This is a manual focus lens, so I got a lot of practice with being fast with the manual focus with all these moving subjects!