A recent study has shown that the air pollution in the New York City subway system is severe, with concentrations of PM2.5 fine particulate matter exceeding safe levels by several times, reaching a level of “abnormally severe” that poses a threat to health.
The study, conducted by New York University, was published on August 6th in the journal “PLOS One.” It found that the average PM2.5 concentration in subway stations is four times higher than the U.S. Environmental Protection Agency’s (EPA) safety standard of 9 micrograms per cubic meter (µg/m3) and nine times higher than the World Health Organization’s (WHO) safety standard of 5 micrograms per cubic meter, reaching an “abnormally severe” level of air pollution.
PM2.5 refers to particulate matter with a diameter equal to or less than 2.5 micrometers (μm) in the air, known as fine particulate matter, which can penetrate the human lungs and even enter the bloodstream, leading to cardiovascular, respiratory, and neurological diseases. The abnormally severe air pollution in the New York City subway system means that the longer one spends commuting on the subway, the higher the exposure to PM2.5 air and the greater the health risks.
The study was led by Professor Masoud Ghandehari from the Department of Civil and Urban Engineering at New York University. Researchers found that the friction of metal wheels and brakes on the tracks releases metal particles, with concentrations of these particles particularly high when trains arrive at subway stations. Approximately 15 to 20 seconds after a train departs, the concentration of metal particles slowly decreases, indicating that materials at the bottom of the subway tunnels are disturbed, leading to a deterioration of air quality.
The study paper mentioned that subway stations with high levels of particles include the 168th and 181st Street stations on Line 1, Bowling Green station on Line 5, and Broadway-Lafayette St station on the B line.
This study by New York University analyzed the commuting data of 3.1 million workers in the city’s four boroughs (Manhattan, Brooklyn, Queens, and the Bronx). It found that low-income residents living further from the city center and black and Hispanic individuals, who rely on long subway commutes, have a higher exposure to PM2.5 air compared to other ethnic groups. The PM2.5 exposure values for black and Hispanic workers were 35% and 23% higher than Asian and white commuters, respectively.
Furthermore, minority workers in Upper Manhattan and the Bronx, where employment opportunities are fewer, had the highest exposure to PM2.5 due to long subway commutes.
Researchers also created an interactive map for commuters to calculate their personal PM2.5 exposure from their departure point to their destination, accessible at: https://tinyurl.com/y95u4k62
This news outlet contacted the MTA for comment but had not received a response by the time of publication.