The next time you're waiting the endless wait for the Sunday night G train, take a big, deep breath. Yes, there's urine, mingling gently with the stench of sour trash, but there's something else—something you can't quite put a finger on. Ah, yes, you know that scent: The unmistakeable fragrance of human flesh. Eau de Epidermis.

A study [PDF] conducted by the University of Colorado from 2007 and 2008 to "determine the composition and diversity" of the gross shit you breathe on the subway (paraphrased), reveals that in addition to dirt and other organic matter, 15 percent of the material analyzed was human skin.

The skin in question appears to come mostly from from feet, hands, arms, heads, but also such exotic locales as ears, belly buttons, the space between your eyes, and, thanks primarily to this guy, butts! There was also the presence of "wood rot fungi," likely complements of the wooden tracks.

Oh, but don't worry, say the scientists from their temperature-controlled laboratories in the tree-filled utopia of Colorado— there's no cause for alarm. Thanks either to the MTA's excellent air circulation—or perhaps the inescapable filth blanketing all of New York City—there's no notable difference in content between the air you breathe in the city's most populous subways and, say Union Square Park. Between that and the "totally harmless gas" that will be blasted through stations around the city this summer, it might be worth taking a cue from this guy.