Air quality alerts and advisories have been issued in multiple states as Canadian wildfire smoke continues to spread.

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 wildfires raging in Canada has drifted into the United States, affecting air quality as far south as Florida.