A smog warning issued by Environment Canada Saturday for the greater Montreal area — including Châteauguay, Laval and Longueuil — remained in place Sunday.
The agency warns that smog can cause complications, especially for children and people with respiratory issues, asthma or heart disease.
Environment Canada recommends that these individuals avoid intense physical activity outdoors until the smog warning is lifted.
According to meteorologists, wood heating is the main source of fine particles that contribute to smog during winter, in Quebec.
Cold temperatures combined with low wind speeds are causing the fine particles to remain trapped at the surface, leading to poor air quality.
To help improve the situation, the agency suggests limiting the use of fireplaces and wood-burning stoves and using public transit more often.
Environment Canada said the poor air quality will persist until Monday.