So, you know that the subway is going to be a breeding ground for various bacteria and viruses. If you travel on there on a regular basis, then there is every possibility that you will pick up all kinds of illnesses, and it is often due to the air that you are breathing in.
However, even though we do seem to kind of accept that this is the case, it seems that a rather surprising percentage of the air is made up of something that you are probably going to feel a bit sick about when you think of it entering your body.
You see, it is believed that in a typical subway station that approximately 15% of the air content actually consists of particles of human skin. Now, just stop for a moment and imagine all of that coming into your mouth and then your lungs. Does that not make you want to stop what you are doing and reconsider how you are going to be breathing when you next venture into the subway?
Perhaps the Japanese had the correct idea when it came to wearing those masks.