Meteorologists with Environment Canada have issued a Special Weather Statement for some western areas of northwestern Ontario.
They say smoke from forest fires in Manitoba and northwestern Ontario could cause "high levels of air pollution" around communities from Morson in the Rainy River District north to Pikangikum, Poplar Hill and Sandy Lake, and as far east as Lac Seul.
Environment Canada cautioned on Thursday morning that air quality may deteriorate if the smoke descends to ground level.
People may experience symptoms such as increased coughing, throat irritation, headaches or shortness of breath.
Meteorologists expected that southerly winds developing later in the morning or early afternoon would likely cause most of the smoke to dissipate, but at some time may also push the smoke into far-northern Ontario.
