Most people associate smog with the warm sunny days of summer, but it actually occurs more frequently in winter because of the use of wood-burning heat, which produces smoke containing air pollutants. In 2010, for example, there were 17 smog days in the winter compared to 7 in the summer on the island of Montreal. Air pollution can have adverse effects on health and the environment. To determine whether the concentration of pollutants is likely to reach damaging levels, it is important to monitor smog warnings and air quality forecasts, available at Environment Canada’s Info-Smog website.

Winter smog
Smog consists of air pollutants that form a yellow haze over cities, but it can also occur in suburban and rural areas. In the winter, smog is generally a local phenomenon that is exacerbated by cold weather and occurs when the air is stable (little wind). Fine particles play a significant role in the formation of smog. While industrial activities and public transportation are the main sources in the summer, fireplaces and wood-burning stoves are responsible for more than 60% in the winter. Motor transportation and road salt, suspended in the air by passing cars, also degrade air quality.

Impacts of smog on health
Fine particles, which are too small to be visible to the naked eye, can penetrate deep into the lungs. Children with asthma and those with cardiovascular or respiratory disease may be affected the most and experience aggravated symptoms of their illness. During smog periods, these people should avoid intense physical activity outdoors.

Improving air quality
Everyone can contribute to better air quality by avoiding wood-burning heat and choosing public transportation. When using a car is necessary, it is important to reduce speeds and not let the car idle unnecessarily. These are simple measures that everyone can take on a daily basis, but that are particularly important during smog warnings.


As a reminder, Info-Smog is the air quality forecast and warning program provided by Environment Canada in partnership with the Ministère du Développement durable, de l’Environnement et des Parcs du Québec, the City of Montreal, the Ministère de la Santé et des Services sociaux du Québec and the Direction de santé publique de l’Agence de la santé et des services sociaux de Montréal.

Source: Environment Canada, MONTREAL, Que. — December 19, 2011

This site is protected by

%d bloggers like this: