Much of northeastern Minnesota remains under air quality alert Friday, while a second alert covering the northwestern part of the state will go into effect on Saturday.

When to expect the heaviest Canadian wildfire smoke in Minnesota this weekend originally appeared on Bring Me The News. All of Minnesota will experience poor air quality this weekend as smoke — both near the surface and at higher altitudes — invades from wildfires that are burning out of control in Canada.

Minnesota authorities warned of unhealthy levels of exposure to particles from wildfires. Symptoms include shortness of breath, heart attack. stroke.