The Michigan Air Quality Division said as smoke from Canadian wildfires continues to threaten the upper Midwest, "monitors in the western (Upper Peninsula) showed a large increase surface concentrations, during Tuesday, as smoke mixed down, which sent PM-2.5 concentrations soaring into the Unhealthy and higher range."

Maps show where new plumes of smoke will cause hazy skies through the end of the week. Low-level smoke is forecast to spread eastward Wednesday across the Appalachians and into the Mid-Atlantic and Northeast.