The island of Montreal has, on average, 65 days of poor air quality a year.

In most of these cases, fine particles are at fault. Although fine particles come from a variety of sources, e.g., cars, trucks and industry, the majority come from wood heating, and thereby contribute to winter smog. A conventional wood stove burning for only nine hours emits as many fine particles as a car does in one year (18,000 km of driving). On days where there are a large number of wood stoves and fireplaces in use, AIR QUALITY can be worse in some of MONTREAL's residential areas than it is downtown.