Canada’s seemingly endless wildfires in 2023 introduced millions of people across North America to the health hazards of wildfire smoke. While Western states have contended with smoky fire seasons for years, the air quality alerts across the U.S. Midwest and Northeast this summer reached levels never seen there before.

Wildfires in Canada have caused a smoky haze over the Old Capitol dome, leading to an air quality advisory in eastern Iowa. Charles Stanier, an expert in airborne contaminants, explains the causes and impacts of the poor air quality, including short-term health risks and long-term effects on outdoor activities. The AirNow website and app provide information on daily air quality.