A study published in 2021 to the journal of Environmental Health Perspectives sheds light on the disturbing findings regarding the air within East Coast subway stations, most specifically New York’s.
In an attempt to survey air quality surrounding subway systems on the East Coast and how it affects travelers and commuters, researchers collected air quality samples from a total of 71 stations across subways in NYC/NJ area, Philadelphia, Boston and Washington D.C.
What they found were high levels of particulate matter (PM2.5) and particle composition during rush hour across the East Coast cities (both morning and night). To clarify, PM2.5 is defined by the United States Environmental Protection Agency as inhalable particles, generally 2.5 micrometers or less. Increased concentrations of PM2.5 can lead to serious health implications such as aggravated asthma, decreased lung function, nonfatal heart attacks and so on. Iron and organic carbon were the primary components of the particulate matter found.
“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,” said study lead author, David Luglio.
To determine which NYC stations were analyzed, the researchers targeted stations that were already recorded to have increased PM2.5 from an earlier study from the National Center for Biotechnology Information. These point of collection sites included 35 platforms across 30 NYC subway stations along five MTA lines.
Out of the entire study, the highest concentration of airborne particles were found in the PATH system with 392 micrograms per cubic meter. In fact, the exposure levels found in the PATH system were higher than any previously recorded value for all subway stations around the world. According to the EPA, fine particle concentration exposures can become hazardous when they exceed a daily 35 micrograms per cubic meter.
Furthermore, the most polluted station in the study was found at the Christopher Street PATH station during morning rush hour. Daily commuters on the Christopher Street PATH station could assumably be at an increased risk of cardiovascular mortality by 11% under certain assumptions.
Moreover, underground stations across the East Coast cities in the study were observed to have double the amount of airborne particle concentrations than their outdoor sample equivalent. It’s important to note that the study found no severe levels of contamination, even among the worst samples.
Further investigation on the source of subway air contamination, which could potentially include dust left behind by deceased rodents, exhaust from diesel locomotives, and poor ventilation, was promised by co-senior study author and Department of Medicine professor at NYU Langone, Dr. Terry Gordon.