(Undated)– For days smoke from wildfires burning in Alberta and Saskatchewan, Canada could be seen throughout the region aloft. Thursday, that smoke has made it to the surface, even limiting visibility.

It’s also causing concern over air quality. The entire state of Minnesota is under an air quality alert. The Minnesota Pollution Control Agency (MPCA) says it will remain in effect through 6:00 am Friday (May 19th.) A similar alert is in effect for all of Nebraska. While such an alert has NOT been issued for Iowa, the smoke is also affecting air quality there.

The MPCA says those suffering from asthma, heart disease and other respiratory conditions should limit the time they spend outdoors, and that everyone should avoid prolonged or heavy exertion.