Smoke from wildfires is expected to cause poor air quality and reduced visibility in Renfrew County, according to an alert issued by Environment Canada on Thursday.

Wildfire smoke was helping raise ozone to hazardous levels. No alerts have been issued, but the air quality may approach “code orange” levels again late Thursday afternoon in parts of the region, as it appears that the ozone factory will still be operating while the Canadian wildfire smoke persists in the skies over Philly.

Smoke from Canadian wildfires continues to plague the Upper Midwest and Great Lakes region, with multiple states under air quality alerts.