Smoke from Canadian wildfires is causing air quality concerns for millions of Americans in the Midwest and Northeast. Air quality alerts were in effect Tuesday in several states, including Wisconsin,

Hazy skies descend over the New York City area again on Tuesday, re-upping some air quality alerts related to Canadian wildfire smoke. As of 9 a.m., the air quality index was 118, which is considered unhealthy for sensitive groups.

Air quality alerts are in effect on Tuesday in 10 states as toxic smoke from hundreds of wildfires burning in Canada continues to waft into the United States, creating hazy, gray skies over major metropolitan areas, including New York City.