Study of Subway Air Pollution for Boston, NYC, PATH, Philadelphia, and DC

An extensive pre-pandemic study of Particulate Matter (PM) and Black Carbo (BC) was conducted at ~ 130 subway stations (both above ground and below ground) as well as on the trains themselves.

Excerpts:

Led by NYU Grossman School of Medicine researchers, the study measured air quality samples in 71 stations at morning and evening rush hours in Boston, New York City, Philadelphia, and Washington, DC. Among the 13 underground stations tested in New York, the investigators found concentrations of hazardous metals and organic particles that ranged anywhere from 2 to 7 times that of outdoor air samples.
Notably in the report, published online February 10 in the journal Environmental Health Perspectives, one underground platform on the PATH line connecting New Jersey and Manhattan (Christopher Street Station) reached up to 77 times the typical concentration of potentially dangerous particles in outdoor, aboveground city air. This figure is comparable to sooty contamination from forest fires and building demolition, the study authors say.

Air quality was also measured in another 58 stations during rush hours in Boston, Philadelphia, and Washington. While no station’s readings reached the severe levels of contamination seen in New York’s worst transit lines, underground subway stations within each of these cities still showed at least twice the airborne particle concentrations as their respective outside samples at morning and evening rush hours.

“Our findings add to evidence that subways expose millions of commuters and transit employees to air pollutants at levels known to pose serious health risks over time,” says study lead author David Luglio, a doctoral student at NYU Grossman School of Medicine.

Summary data of air samples collected from various MBTA subway stations is attached as images.

Link to NYU Langone Health press release: https://nyulangone.org/news/pre-covid-1 ... tudy-finds

Link to the report: https://doi.org/10.1289/EHP7202

At least they didn't find the infamous "Subway Microbe" that the Boston Post in 1897 claimed lurked in the Tremont Street Subway:


I do wonder regarding the surface stations how much of the PM and BC readings are coming from the major arterial roads or highways that are in close proximity to each of the stations.

No doubt ballast, concrete, and brake shoes all create a lot of dust. Some properties have or had used vacuum trains and tunnel wall washers to remove or mitigate dust. Perhaps it's time to look into that being a regular maintenance activity on any subway system.

I'd like to know what the composition of the particles they found is. Presumably steel dust and brake shoe dust are the big offenders, but is there anything else?

+1. Lack of detail on what they found. On the T my nose says you are breathing lots of volatiles from lubricants + dust + perhaps mold or mildew? Dust would consist of semi-metallic brake pad materials + asbestos from years ago. You could also have ozone from arcing but I don't remember that.

In the original post, reference was made to high pollution levels near the Christopher St PATH stop. That station is only a few blocks from the NYC entrance to the Holland Tunnel and during pre-Covid times there were lots of cars jamming the nearby streets heading for the tunnel to leave the city. Maybe that helps explain the high pollution?

Just another reason to wear a mask(s) long after covid-19 ?

Those of us of a certain age will remember the "NO EXPECTORATING UPON THE PLATFORM" signage that was incorporated into the white subway tile walls of subway stations. Both the signage and the tiles were to promote underground health when Boston's subways were first built and tuberculosis was more prevalent.
Mebbe the combination of trying to look less like a quarantine zone and more modern plus budget cuts led to dimmer illumination and darker walls in the 70s and later.

Right... if you use dim lighting and dark walls, you can't see the dirt, and if you can't see the dirt, it's not there, and if it's not there, no money need be allocated or spent to clean it... VOILA! Budget problems solved!