Smoke from Canadian wildfires continues to affect air quality across the Midwest, though Monday’s conditions were an improvement for most of the Chicago area.

Smoke from Canadian wildfires is causing air quality concerns for millions of Americans in the Midwest and Northeast.

At least three people have been injured and hundreds of homes and businesses are at risk in California as a massive wildfire spreads across the Los Padres National Forest. Smoke blowing over Las Vegas from the California wildfire created a hazy sky and poor air quality over Sin City Monday.