With the city once again blanketed in wildfire smoke, experts are warning that long-term exposure to air pollution can lead to higher risk of heart failure.

Environment Canada issued a special air quality statement on Sunday night due to wildfire smoke from northern Ontario pushing Toronto’s Air Quality Health Index to 10+, classified as “very high risk.” Poor air quality was expected to persist Monday and possibly into Tuesday.

The effects of air pollution on the heart are underscored in a recent study, which found that long-term exposure to air pollution, in particular fine particulate matter, was linked to higher levels of diffuse myocardial fibrosis, a type of heart scarring that can lead to higher risk of heart failure.