Smoke from forest fires will pollute Toronto's air again this week

Environment Canada issued a special air quality statement for Toronto Tuesday afternoon, advising that high levels of air pollution will develop in the evening due to smoke from forest fires. 

Smoke plumes from fires over northeastern Ontario and Quebec will move into Toronto overnight, "resulting in deteriorated air quality," it said. 

Those conditions may only improve by Friday morning, it said. 

The air quality statement marks another week where wildfire smoke will pollute Toronto's air. The city was last issued a poor air quality statement just over a week ago, and experienced days of smoky air earlier in the month. 

As of Tuesday night, Toronto's air quality is predicted to reach a six on the 10-point Air Quality Health Index (AQHI) scale, which measures air quality based on how it will impact health. A six indicates a moderate level of risk, which means there is no need to cancel outdoor activities unless people are coughing or their throats are irritated.

By Wednesday, the air quality is predicted to worsen to a seven, which indicates a high level of risk. 

The weather agency said for that level of pollution, those considered at risk should consider cutting back on or rescheduling strenuous outdoor activities if they are experiencing symptoms.

People at risk include seniors, infants, children, pregnant people, those who work outside or engaging in strenuous outdoor activities, and people with chronic health problems such as cancer or diabetes. 

Those who are not considered high risk should monitor their symptoms and cancel activities if they experience illness, the agency said.