Packed in among your fellow sniffling, coughing straphangers, trying to stay upright on a swaying train, you eye the subway pole.
A lot of people have been touching that pole.
You don't want to catch a cold (or worse), but you don't want to fall. What to do?
An expert on the genetic material littering our underground transport system says go ahead and hold that pole. Just wash your hands afterwards.
Christopher Mason is a geneticist and associate professor at Weill Cornell Medicine who recently undertook a massive DNA sampling of the New York City Subway. He says while most of the surfaces you touch on the subway are covered with bacteria, human DNA and some viral DNA, they are usually harmless.
"The things you're most worried about," he said, "viruses that actually might get you sick, a lot of them don't last long at all on most surfaces. So the perception you can't touch any surface on the subway on the way home is actually a little paranoid because most surfaces most of the time are really benign."
Mason says it's important to note there is a difference between simply touching something with intact skin, versus actually putting something IN your body, like by eating or rubbing your eyes with dirty hands.
And of course, a lot of people have just touched the pole. So Mason says it's always a good idea to wash your hands when you get where you're going. Especially if you've touched something mysterious.
And don't do this:
(That's YouTube video that went viral in 2012.)
When it comes to contracting a virus from the air — as opposed to the surface — you are actually safer on the subway, Mason says. While there may be a lot of sneezing and coughing, Mason says the relative humidity underground means those airborne germs will fall to the ground quickly.
In fact, he sees a sort of beauty in grabbing the subway pole.
"I like to think riding the subway is like shaking hands with 10,000 people," he said, "which I like to think is this beautiful echo of humanity."
But he added "If you don't like shaking hands with lots of people you might find that less soothing."
Hypothesis is written and produced by Alec Hamilton and edited by Matthew Schuerman. Sound design and engineering by Liora Noam-Kravitz. Original music by Josh Burnett.
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