An Air Quality Advisory is in place for the Cowichan Valley.
The advisory was issued by Island Health and the Ministry of Environment.
Medical Health Officer Doctor Charmaine Enns says the level of fine particulates has risen to a level that could impact those with underlying health conditions.
She says the stable, cold air mass over the region is trapping the particles near the surface.
Enns says the particulate level will likely stay elevated until the weather changes.