An air quality monitor tests the conditions at Union Square. (Photo via flickr user wwward0)
It’s not secret that the subway system is not the cleanest spot in New York City. The dirt, grime and garbage is evident on platforms and trackbeds and fills tunnels and even train cars as well. Some people brave the mess to grab a quick bite to eat, but we’re all better off not dwelling too much on the cleanliness, or lack thereof, underground. But what of the air quality?
The odor of the subway is often distinctive and, depending upon location, unique. The 2nd Ave. station smells like the 2nd Ave. station, and a few other underground stations are signature smells. Generally, though, the subways smell like some combination of the unwashed masses mingled with various bodily odors, the scent of food or garbage and often, if we’re lucky, nothing. But that doesn’t mean we’re not breathing in various microbes, metal dust and other assorted things.
It’s hard to believe, but in all of the years of subway operations, scientists haven’t taken a close look at the air down there. A group of scientists out of Colorado have taken it upon themselves to do just that, and they’ve released their findings [pdf]. “The goal of this study,” they said, “was to determine the composition and diversity of microorganisms associated with bioaerosols in a heavily trafficked metropolitan subway environment.”
With that in mind, the paranoid among us may cast a wary eye upon its findings, but the study should assuage those fears. “We encountered no organisms of public health concern,” the researchers noted. But what did they find? In a nutshell: “The microbiology was more or less similar throughout the system and with time, and most similar to outdoor air, consistent with highly efficient air mixing in the system. Identifiable bacterial sequences indicated that the subway aerosol assemblage was composed of a mix of genera and species characteristic of soil, environmental water, and human skin commensal bacteria.” Essentially, we’re breathing in the same things underground as we do above ground.
The study went into more detail:
The subway environment, underground and away from light, might seem remote from our usual environment and potentially occupied by distinct or novel kinds of microorganisms. Rather than unusual however, our survey finds that the microbiota encountered in the NYC subway is fairly mundane, essentially a mix of outdoor air with an overlay of human-associated microorganisms typical of the skin. No significant evidence of pathogens or other organisms of concern was obtained, beyond what might be encountered in any human-occupied indoor setting. Thus, this survey provides the pre-event information necessary for surveillance activities for pathogens that might occur or be introduced into the system. The results also provide pre-event information necessary for interpretation of the microbiological consequences of the recent flooding of the NYC subway system during Hurricane Sandy in 2012.
Although subways might be considered confined environments, the similarity of subway air microbiota to that of outside air suggests that the subway air significantly equilibrates with outside air on relatively short timescales. There is little or no local air conditioning in the NYC subway. Instead, air movement in the system is driven by passive train-pumping, with air taken in and exhausted through street-level ports, the NYC sidewalk grillwork. The general uniformity of microbial assemblages throughout the system indicates good air mixing, a testimony to the efficiency of the train-pumping process.
Ultimately, the study provides a baseline for air sampling for security detection. By setting levels now, officials can more easily detect living things in the air that shouldn’t be there and that may pose a risk to humans. To that end, NYPD officials plan to release a colorless, odorless, harmless gas into the subway system later this summer to determine how air flow would spread something dangerous in the event of a terrorist attack. “The subways play a major role in how air moves through Manhattan and the five boroughs,” Paul Kalb, an engineer at the Brookhaven National Laboratory, said. “If you’re in the subways and there’s something released on the surface, you could be vulnerable.”
As that express train rushes by you next time you’re waiting for a local, note the wind, and dwell on what may be in that gust of air. It may not always be such a comforting thought.
20 comments
One question I have always had is why the PATH smells SO MUCH different from the subway. It’s completely distinctive. When you walk into the shared PATH / 6th Ave Line station at 23rd St., you could close your eyes and navigate to the PATH or the F by smell alone!
It’s more of a musty, dank, cardboard (attic?) smell on the PATH platforms.
I was told it was a combination of the general underground dank subway air, mixed with PATH’s exposed cast-iron rings, that created the system’s unique smell.
Other than the oppressive summer heat on the IRT platforms, I never considered Union Square one of the stations that had a distasteful odor — if anything, growing up it smelled of baked pretzels from the stand in the station. The south end of Second Avenue or some of the moldier stations in the system would be the real test for the equipment (I personally would like to see them try it out at Chambers Street on the J/Z, if for no other reason than to see something that looks like a dwarf patio heater sitting amid the ruins of the unused south side platform, like some time-traveling probe that’s arrived in Earth’s post-nuclear holocaust future).
I’d wondered that about the PATH as well; thanks for the info, John-2.
I think the real environmental danger in subway stations is noise: http://www.ncbi.nlm.nih.gov/pm.....MC2438596/
Has there ever been talk of noise abatement strategies in the worst stations? Is the MTA required to comply with any OSHA/EPA regulations regarding noise exposure for riders? Sitting on the platform in Union Station for 5 minutes listing to the trains screech by is enough to give me a headache, and the MTA seems to think the solution is to just make the competing noises even louder by upping the volume on the public address system (but not the clarity) and granting permitted music performers seemingly free reign to turn up their amps to ear-splitting levels. And people wonder why everybody’s got earbuds in while they commute these days…
Other than the rail lubricators — which only slightly moderated the noise at South Ferry — I don’t know what you can do to alleviate Union Square’s 109-year-old design flaw of putting the station in the middle of a major curve (I suppose soundproof platform doors might be an option, but the current staircase positioning at the stations and the need to clear room for the platform extenders also would create problems there).
(Union Square should have been built either between 14th and 12th Streets like the IRT 7th Avenue stop, or between 15th and 17th streets, which would have saved building the 18th Street local stop in the first place. But to rebuild Union Square like that today, or even just redoing all the stairs for platform doors while keeping the Lex running normally would be cost prohibitive).
Keep in mind that the original IRT platforsm were configured for three-car trains, and were only expanded later in the 1920s and 1950s to accommodate the ten-car consists of today. The original Union Square IRT platforms are those very straight portions on the southern end of the station, so all that screeching was originally limited to the tunnel, not the station. When they extended the platforms northward (and closed the local platforms that can still be seen along the side walls) they had nowhere to go but into the curved tunnel, hence the screetchyness.
I thought IRT the express platforms were always full-length, while it was the local platforms that were the ones in need of expansion over the years.
Uptown Union Square on the 4/5/6 really isn’t that bad, except at the far northern end — it’s the downtown platform that is both painful to the ears and has to deal with the platform extenders (also, except at the far northern end, before the trains hit the curve).
This is an equipment issue. The axles are fixed and thus the wheels will rotate at the same speed. When the curves are sharp enough, the difference in the inner and outer rail curve radius grows to to the point that the inner wheel is rotating faster than its traveling and the outer wheel is rotating slower than the distance its covering. The wheels grind down on the the rails and pushes the outer wheel flange onto the outer rail causing more wear and noise.
If the axles had differentials or the wheels were independent, this grinding noise (an wear and tear) would mostly go away.
Maybe its time to ban food and drink?? enough is enough! we live like pigs and get what we deserve I guess. Plus all the money we’d save from garbarge removal/storage, etc we can re-invest into the system. But it makes too much sense for the MTA so it probably won’t happen, lol.
Agreed. It’s rather disgusting when someone opens up a food bag/box and starts eating on the train. The whole car fills with the odor. One time someone sitting right next to me started eating sushi!
It’s just bizarre to be eating on a train with everyone else sitting/standing there and knowing it.
But it won’t stop all the garbage and it really can’t be enforced anymore than littering.
Littering is scarcely enforced at all. It would be quite easy to enforce if they bothered.
Well, I sort of take that back. The fine does need to be higher for it to be worth bothering.
I vote for cuffing 13-year-old girls who eat a french fry.
Verily, you belong on a tribunal of last resort.
DC does not allow eating, and some yrs back, I recall, a teen girl was ticketed and possibly arrested for eating on the subway. Then all the bleeding hearts went into action, attacking the system for its heartlessness.
And ultimately, nothing further happened. Eating still isn’t allowed, and the DC subways are significantly cleaner than New York’s.
What those “bleeding hearts” (i.e., those of us who believe in silly things like due process and human rights) were objecting to was the heavy-handed reaction by the thug WMATA police to the matter. They couldn’t be satisfied to simply fine her or, if she really misbehaved, call her mommy. They had to cuff a 12-year-old and stick her in a paddy wagon and send her through the juvenile justice system. Over eating a fucking french fry.
I suggest you remain in DC.
I think the 4/5 platforms at 59th Street have the worst/unhealthiest smell.
P.s. Thanks for the explanation of why PATH smells differently than the subway.
Very interesting stuff. I’d be curious about other kinds of air-quality reports. I don’t know what the brakes are made of, but between those and the rails, there has to be a ton of metal dust. I’m sure there’s all kinds of non-organic stuff floating around down there.