New York City’s subways have a reputation for being dangerous, but a new study has found that the air is also deadly.
Commuters face deadly pollution levels on the subway that are up to 10 times higher than what is considered a safe limit, a new study reveals.
Researchers studied levels of particulate matter (PM2.5), tiny particles released during combustion, which can reach deep into the lungs and bloodstream, where they cause damage linked to cancer, cardiovascular disease and premature death.
The team found that the average concentration of pollution on platforms was 139 micrograms per cubic metre and 99 micrograms per cubic metre on trains, compared with the World Health Organisation’s limit of 15 micrograms.
Researchers studied particulate matter (PM2.5) on train platforms and carriages and found that passengers are exposed to excessive levels of iron from trains.
However, the World Health Organization limits are based on 24-hour exposure, while many travelers breathe that amount while spending 30 minutes on their journey or 10 to 20 minutes standing on a platform waiting for a train.
Studies have shown that even breathing PM2.5 for a few hours can cause breathing problems, especially in people with asthma and other respiratory problems.
Researchers at New York University (NYU) End-to-end round-trip travel was analyzed across 19 subway lines and 368 stations, using data from 3.1 million residents.
Measurements were taken in each subway car and at each stop while on the platform.
Levels peaked when the train pulled into the station. It was discovered that its abrupt stop would stir up existing contaminants that had built up in the tunnel over the years.
The rubbing of the metal wheels and brakes released metal particles that made up a large amount of the particle concentrations.
Masoud Ghandehari, a professor at New York University and lead author, said: Bloomberg‘We noticed that when a train arrives at the station, the concentration in the air shoots up, and about 15-20 seconds after it leaves, the concentration slowly decreases.
‘This implies that what is at the bottom of the tunnel is what is stirred up and deteriorating the air.’
PM2.5 comes from cars, coal-fired power plants, trains and burning waste – common activities around the world, no matter where you live.
Pollution does not directly kill people, but it degrades their overall health and leaves them vulnerable to developing a variety of diseases, such as lung, brain and heart problems that can eventually lead to death.
The researchers also found that when pollution was combined with poor ventilation at some stations, mainly in low-income areas such as the Bronx, it generated higher concentrations of particulate matter.
The team found that the average concentration of pollution on platforms was 139 micrograms per cubic metre and 99 micrograms per cubic metre on trains, compared with the World Health Organisation’s limit of 15 micrograms.
According to the study, published in PLOS One, black and Hispanic workers faced exposure levels that were 23 percent higher than white commuters, due to the time they spent commuting to work and different levels of pollution on station lines.
“Most of the jobs are in New York City’s financial districts, (such as) midtown and central Manhattan,” Ghandehari said. The Guardian.
“People with lower incomes tend to live further away from these workplaces, so the time it takes them to travel is longer, which means their exposure will be greater.”
Residents living in Upper Manhattan neighborhoods, including Washington Heights and Inwood, had the highest levels of exposure to subway pollutants due to the length of their commutes, the study found.
This was compared to those living in Midtown Manhattan, where people can live closer to their workplaces.