“Air quality and visibility due to wildfire smoke can fluctuate over short distances and can vary considerably from hour to hour,” Environment and Climate Change Canada (ECCC) said in its statement.

Canada is battling more than 700 active wildfires across the country, roughly two-thirds of which are burning out of control, according to the Canadian Interagency Forest Fire Center (CIFFC). Smoke billowing from the blazes has blanketed central Canada and the northern U.S., prompting widespread air quality alerts.

On Monday morning, Environment Canada issued a special air quality statement for the vast majority of southern Ontario, predicting "poor air quality" as a result of forest fires.