News Release
January 6, 2020

In a response to a request from the Board of Health to conduct a study of the health impacts of air quality for passengers in the subway system, Toronto’s Medical Officer of Health will present a report at the January 13 board meeting. The report shows that taking the subway benefits the overall health of all Toronto residents and that these benefits would be further enhanced by the implementation of short-term and long-term measures to improve subway air quality.

Fine particulate matter air pollution (known as PM2.5) is present in indoor and outdoor air, and in public transit systems in other cities. The report identified that levels of PM2.5 in Toronto’s subway system warrant mitigation because reductions would have health benefits for passengers. The abbreviation PM2.5 refers to particles in the air that are less than 2.5 microns in diameter. These particles are about 20 to 30 times smaller than a human hair.

Toronto Public Health is recommending that the TTC implement measures to reduce exposure to PM2.5 levels in the subway system. This could include employee training, reviewing TTC operations to identify where PM2.5 exposure can potentially be reduced and ongoing air quality monitoring.

While there are opportunities to improve subway air quality, this independent study concludes that there are many health benefits of taking the TTC including:
• providing an opportunity for physical activity such as cycling or walking to and from transit, which helps prevent heart disease, diabetes and some types of cancers
• reducing outdoor air pollution and greenhouse gases, which contribute to climate change. (The TTC estimates that during rush hour, each subway train replaces 900-990 personal vehicles that would otherwise be on the road.)  
• supporting access to employment opportunities, education and health services that contribute to overall health and well-being.

More information about the report is available at


“As Toronto residents, my family and I often rely on the TTC for our daily commutes because it is convenient and a healthy way to get us to our destinations. Taking public transit is a simple way to incorporate physical activity into our day by walking in between modes of transit, and it benefits everyone in our community by reducing traffic congestion and air pollution. We prepared this report following a request from our Board of Health and are recommending ongoing mitigation strategies so that residents have continued access to an excellent transit system which is an important feature in a modern, growing city.”
– Dr. Eileen de Villa, Toronto’s Medical Officer of Health

“The TTC thanks Toronto Public Health for its review and concurs with the report’s recommendations for short and longer term measures to improve subway air quality for our employees and customers. The health and safety of all who work on, and ride the subway system are of paramount importance to the TTC. Over the past three decades, the TTC has addressed air quality levels with the introduction of new vehicles, improved ventilation and filtration systems. We remain fully committed to continuing our world-leading efforts in air quality mitigation by monitoring the effectiveness of our actions to date and ensuring mitigation is factored in to all aspects of our subway operations and procurement. We will also exchange information and discuss best practices with other large transit systems like New York and London where similar challenges are faced.”
– Rick Leary, TTC CEO

Toronto is Canada’s largest city, the fourth largest in North America, and home to a diverse population of more than 2.9 million people. It is a global centre for business, finance, arts and culture and is consistently ranked one of the world’s most livable cities. For information on non-emergency City services and programs, Toronto residents, businesses and visitors can visit, call 311, 24 hours a day, 7 days a week, or follow us on Twitter at, on Instagram at or on Facebook at

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Media contacts:
Lenore Bromley, Toronto Public Health, 416-338-7974,
Stuart Green, TTC, 416-393-3898,