Fifteen percent of the air you breathe in a metro station is human skin.
A study conducted by the University of Colorado from 2007 and 2008, reveals that in addition to dirt and other organic matter, 15 percent of the material analyzed was human skin.
Source: http://gothamist.com/2013/05/09/when_you_breathe_on_the_subway_you.php
Tags: Breath Human skin
