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,

Air quality has taken a serious hit across the United States as a two-fold 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.

Each New England state has seen an uptick in the number of days over the last five years when fine particulate matter (PM2.5) or ozone exceeds air quality standards that are considered “unhealthy for sensitive groups.