We’ve all been there at some point. Packed into subway cars that feel like sardine cans and cause claustrophobia unlike any other. We wonder, even fleetingly, what subway air is really made of. Or, as the University of Colorado-Boulder’s new study phrased it: what is the microbial content of the air in the subway system? How much of that musty subway air is made up of organic material like fungi and bacteria?
The annual “Shmutz” study done by the Straphangers Campaign reported that the percentage of clean subway cars drops every year. While 52% of subway cars were ‘clean’ in the survey conducted in the fall of 2011, it fell to 42% in the fall of 2013– a statistically significant dip that marks the perpetuation of this general trend in decline. When studying which rail lines are the most and least clean, they found that according to their survey done at the end of 2013, the D-train had the smallest number of clean cars, at a pitiful 17% compared to the 49% back in 2011. The best performing line was the L-train, with 63% of its cars rated clean.
Dr. Norm Pace, a professor of biology Yeshiva University says, “A lot of people think the subway air is pretty dank… and that was the basic question: are the microbes we encounter of concern?” In short, the answer is no. The study, published in the Applied and Environmental Microbiology journal, reports that the air inside subway stations is actually remarkably similar to that above ground.
The University’s main study objective involved the collection of several cubic meters of air from subway stations around New York over the course of 16 months. Their findings– which came at a surprise to the unassuming, yet cynical biology student that I am–were that the microbial content inside the subway is really no different than that of the air on the streets. This discovery is actually a testament to the subways’ air circulation pumps. Despite human traffic of over 1.6 billion people annually, subway platform air and outdoor air stay relatively the same. New Yorkers can breathe easy.
Pace says, “Our survey finds that the microbiota encountered in the NYC subway is fairly mundane.” The air in fact, is essentially a “mix of outdoor air with an overlay of human-associated microorganisms typical of the skin,” which derive mostly from hands, arms, heads and feet called the ‘convective plume’ – a cloud of skin particles that rises from our bodies when we emit heat. Though it sounds slightly offensive, it is surprisingly pervasive in our everyday lives and nothing to worry about. Skin microbiota are found everywhere from classrooms to coffee shops.
In addition, there is a doubled density of fungi in subway stations which researchers speculate is the result of wood rot. However, they maintain that it is harmless to your health.
So the next time you’re sitting (or standing at rush hour) on one of the New York trains, I personally recommend the following: rather than ponder the microbial content of the air you are ingesting, think instead about one of the most fascinating scientific discoveries. The air we breathe is composed of gases that have been on earth for thousands of years, with the exception of the occasional meteor, little carbon, oxygen, and nitrogen that are lost to outer space or introduced into our atmosphere. Thus, it has been hypothesized that the very air molecules we breathe are the same as the ones breathed by dinosaurs, Julius Caesar, and even Albert Einstein.
And though the ‘convective plume’ mentioned above may sound repugnant in the context of a subway, I am comforted by the fact that with every breath I take, I am sharing the same air as those before me. And though my logic may be wholly unscientific and even ridiculous, the far-fetched prospects that such possibilities make me even a drop smarter, or in some way connect me to those in the past, makes the overall subway experience just a little more bearable.