Subway riders and transit workers in major cities are being exposed to levels of air pollution that could increase the risk of heart and lung problems, according to a new study from New York University.
Researchers at NYU Grossman School of Medicine said air quality readings, in particular on the PATH rail system linking New York and New Jersey and New York City’s subway system, raise serious health concerns and warrant further investigation.
The research, published Wednesday in the journal Environmental Health Perspectives, looked at the air quality of transit systems across the Northeast, including subways in Boston, Philadelphia and Washington, during morning and evening rush hours. It found that air quality was lowest on platforms and improved somewhat on air-conditioned trains.
Dr. Terry Gordon, a professor in the school’s Department of Environmental Medicine and a co-senior study author, said all of the systems showed pollution levels at least several times higher than those recommended by the U.S. Environmental Protection Agency. The two systems in New York were the most polluted.
“The only saving grace is that one doesn’t spend much time in the subway system whether on the train or on the platform,” Dr. Gordon said.
Many transit workers do spend most of their career working in tunnels, on stations and on board trains. Richard Clark, a PATH union representative for signal workers, said he found the study alarming.
Mr. Clark said many current and former colleagues suffer from respiratory problems and cancers they believe are caused by their work. He wants the Port Authority of New York and New Jersey, which runs PATH, to invest more heavily in cleaning tunnels, platforms and other areas where pollutants collect.
Port Authority spokesman Ben Branham said Wednesday that the agency would review the study. “We take the issues of health and safety across our facilities extremely seriously,” he said.
Tim Minton, a spokesman for New York’s Metropolitan Transportation Authority, which runs the city’s subway system, said previous air quality tests on its trains found no health risks, “however, we will thoroughly review this study as the safety of customers and employees is always our highest priority.”
Mr. Minton noted that NYU researchers sampled three of the system’s 472 subway stations and four of almost 1,000 daily trains. A spokesman for the union that represents most subway workers, Transport Workers Union Local 100, didn’t immediately comment.
The most polluted stations included Christopher Street station on the PATH and the Second Avenue station on the F subway line.
The NYU researchers believe that many of the pollutants in the subway systems they studied are related to steel dust created by the grinding of train wheels against rails, carbon dust that emanates from a part of a train that touches the third rail and diesel soot emissions from maintenance locomotives.
Steve Chillrud, a research professor at Columbia University who published a landmark study of air quality in the New York City subway system in 2004, said the pollutant levels found by the NYU researchers are concerning.
Dr. Chillrud noted that the NYU research underscored the need for a more detailed investigation, such as an epidemiological study to assess the risk of riding subways. “I think this is a clear call for evaluating the risk in further studies, but it’s not a clear call yet to freak out,” he said.
The research was conducted before the coronavirus pandemic, when weekday ridership on PATH averaged almost 300,000 riders and weekday subway ridership averaged about 5.5 million riders.
Mass transit ridership has plummeted across the country. Transit agencies expect it to recover to near pre-pandemic levels in the next few years.
Dr. Gordon said cloth face masks, which are now ubiquitous because of the pandemic, also reduce people’s exposure to poor air quality. If riders wear masks after the pandemic as many commuters do in Asia, he said, it would be beneficial for people’s health, especially riders with underlying health conditions.