CHICAGO—Hazy, smoke-filled skies from raging Canadian wildfires hovered Wednesday over the U.S. Midwest and East, where millions of Americans were urged to limit outdoor activities as the poor air quality made for dangerous, unhealthy conditions.
Much of the Midwest—from western Iowa through Illinois and Wisconsin and into Michigan and Ohio—was under an air quality alert expected to last through the day and into Thursday or even longer, the National Weather Service said.
