Environment Canada has issued an air quality alert for much of central and southern Saskatchewan.
Smoke from the wildfires north of Hudson Bay is producing poor air quality in all of the south including Regina, Moose Jaw, Swift Current and Weyburn.
The alert also covers the eastern portion of the province up to Cumberland House.
Areas near the fires like Nipawin and Hudson Bay have extremely poor air quality and greatly reduced visibility, Environment Canada said.
The alert for Saskatoon, the Battlefords and Prince Albert has ended.
Air quality should improve from west to east as winds shift to westerly in the wake of a trough of low pressure passing through the province.
The majority of the smoke is expected to clear out of the province by Thursday evening, with the exception being areas near the Manitoba border and downwind of the fires.
Individuals may experience symptoms such as increased coughing, throat irritation, headaches or shortness of breath. Children, seniors, and those with cardiovascular or lung disease, such as asthma, are especially at risk.