A person’s mere presence in a room can add 37 million bacteria to the air every hour – material largely left behind by previous occupants and stirred up from the floor.
We live in this microbial soup, and a big ingredient is our own microorganisms. Mostly people are re-suspending what’s been deposited before. The floor dust turns out to be the major source of the bacteria that we breathe.
All those infectious diseases we get, we seem to get indoors. Learn more here.