Environment Canada says air quality has improved across most of Quebec and Ontario as changes in wind and rain ease the situation east of the Prairies, where wildfires continue to rage.

Smoke from Canadian wildfires is leading to very unhealthy air quality for much of Michigan, including all of Southeast Michigan. An air quality alert is in effect for all of Southeast Michigan until noon on Friday.

Some areas may only see a few hours of alert-level smoke concentrations due to the relatively fast movement of the north-south band of smoke.