The New York subway system is dirty - with human skin.
From 2007 to 2008, biologists from the University of Colorado analyzed air samples that were taken from several New York City subway platforms and found that about 15 percent of the matter that they analyzed consisted of skin.
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Most of the skin came from heels and heads of riders, but 12 percent of the skin came from other areas such as belly buttons, ear canals, armpits and rear ends.
The study found that there was little difference between the air from stations such as Grand Central and City Hall to the air breathed outside in Union Square Park.
The only exception was the increased fungi in the stations, which the study attributed to wood rot fungi on the wooden subway tracks.
"We encountered no organisms of public health concern," the study stated. "The general uniformity of microbial assemblages throughout the system indicates good air mixing, a testimony to the efficiency of the train-pumping process."
The study’s publisher, the American Microbiological Association, wants to use the data that they gathered to analyze the effects of subway flooding and the use of biological warfare.