Canadian wildfire smoke is heading to Maine on Wednesday. Hazy skies are likely and air quality impacts are possible across the state. Hundreds of fires continue to burn across central Canada, and according to the Canadian Forest Fire Centre 91 of these fires are raging out of control.

While the smoke may cloud your vision of the sky or ruin a day at the beach on this week's warmest days of the season so far, it is more than just a nuisance. All across the U.S., the smoke is causing poor air quality, which can cause health effects from mild symptoms in the healthy to dangerous risks for sensitive groups.