Could Riding the Go Train Literally Make You Sick?

A new University of Toronto study has some troubling things to say about commuting on the Go train.

According to the the study, diesel trains might expose passengers to elevated levels of certain pollutants—especially if they're sitting directly behind the locomotive.

"I would advise pregnant women and passengers with heart or respiratory health problems not to travel in the front car," says Greg Evans, professor at U of T’s Faculty of Applied Science & Engineering and director of the Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR) at U of T. "Imagine yourself driving down a busy highway in a convertible, and spending your entire commute sitting behind a very large diesel truck. That's comparable to the levels we see here."

Evans and Cheol-Heon Jeong, a senior research associate at SOCAAR, measured the concentration of airborne particles using instruments that detect black carbon (BC) and ultrafine particles (UFP).

Studies have linked black carbon and ultrafine particles to detrimental health effects, but evidence is not yet conclusive. That said, both are elements of diesel exhaust, which is carcinogenic (meaning it's potentially cancer causing) and associated with respiratory, cardiovascular and reproductive health effects.

"We were quite surprised, and after making confirmation measurements we got in touch with Metrolinx to let them know of the potential issue," said Evans.

Evans and Jeong noted that cars directly behind the locomotive being pulled by diesel trains had an average of nine times the levels of BC and UFP compared to the air next to high-traffic streets, while cars being pushed by diesel trains have air that's generally cleaner than that found near busy streets.

Middle train cars that are being pulled have much lower levels of BC and UFP. That said, the average BC and UFP concentrations across all pulled cars were about five times higher than on city streets.

"The health and safety of our customers and staff is our number one priority, which is precisely why we've supported the work of Dr. Evans and his research team," said Greg Percy, chief operating officer for Metrolinx. "We welcome any findings that can help us run a healthier, safer transit service and we're hopeful this work will result in improvements that will be applied throughout the industry and within other public transit agencies in Canada and abroad."

According to U of T, Percy said that Metrolinx is taking a number of steps to address the issue, including installing high-efficiency filters in the ventilation systems of its train cars. Metrolinx is also moving to locomotives with improved emissions standards and to electrified service on key routes, which will eliminate the diesel emissions altogether.

Evans and his team are currently working with Metrolinx and SNC Lavalin to test the new improved filters for the air intake vents. So far, preliminary results are positive.

"Installing the higher grade filters did produce a marked improvement with an 80 per cent reduction in the levels of black carbon," said Evans.

In the meantime, passengers who have no intention of ditching the train (and really, they shouldn't—public transportation is almost always a great option) can do their part to ensure their ride is as health-friendly possible by avoiding the front train car (especially if they're expecting or suffering from pre-existing health issues.)

"I commute by train on a regular basis myself and have done so for years," said Evans. "As an air quality researcher, I want to see a reduction in overall emissions, and trains are a more efficient system than people commuting in their cars. I don't want to discourage people from taking transit or alarm them unduly, but there is an issue here. It underscores the importance of train electrification, which will address this indoor air issue in addition to helping to combat climate change."

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