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.

Canada wildfires continue to burn, as smoke from the Canadian fires are affecting U.S. air quality in several states, including Indiana. What we know.