Air quality has taken a serious hit across the United States as a twofold blow of wildfires in the West and in Canada have sent smoke pouring across large sections of the country — a problem that’s set to linger for days.

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 10 a.m., the air quality index was 121, which is considered unhealthy for sensitive groups.

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,