State pollution officials are advising Minnesotans to limit outdoor physical activity over the weekend due to smoke from fires in western Canada.

The Minnesota Pollution Control Agency issued an alert Friday that extends through midday Sunday. The agency also advises people to avoid air pollution hotbeds like busy roads and wood fires.

The agency cautions that groups most likely to feel the effects of the “fine particle pollution” include children, older adults, those who have breathing conditions, high blood pressure and people planning to exercise or work outdoors.

Officials say a south wind is expected to usher in cleaner air by Sunday afternoon.