It's Your Health
Smog can cause damage to your heart and lungs - even when you can't see or smell it in the air around you.
When we hear the word smog, many of us picture the chemical "soup" that often appears as a brownish-yellow haze over cities. But smog isn't always visible. It's a mixture of air pollutants, including gases and particles that are too small to see. Smog often begins in big cities, but smog levels can be just as high or higher in rural and suburban areas.
We all need to protect our health against potential damage from smog.
The scientists who study smog are most concerned about the following types of air pollution:
Type: Particulate Matter - or PM. This is the name given to microscopic particles that pollute the air. They vary in size and chemical make-up.
Sources: Industrial and vehicle emissions, road dust, agriculture, construction and wood burning.
Type: Ground-level Ozone. This gas is the result of a chemical reaction when certain pollutants are combined in the presence of sunlight. Ground-level ozone shouldn't be confused with the ozone layer in the sky, which protects us from ultraviolet radiation.
Sources: Ground-level ozone comes mostly from burning fossil fuels for transportation and industry. Ozone levels peak between noon and 6 p.m. during the summer months.
Type: Sulphur dioxide
Sources: Coal-fired power plants and non-iron ore smelters
Type: Carbon monoxide
Sources: Mostly from burning carbon fuels (e.g. motor vehicle exhaust)
Since smog is a mixture of air pollutants, its impact on your health will depend on a number of things, including:
Smog can irritate your eyes, nose and throat. Or it can worsen existing heart and lung problems. In exceptional cases it may result in an early death.
The people most at risk are those who suffer from heart and lung problems. Many of these problems are more common in seniors, making them more likely to experience the negative effects of air pollution. Children can be more sensitive to the effects of air pollution because their respiratory systems are still developing and they tend to have an active lifestyle. Even healthy young adults breathe less well on days when the air is heavily polluted.
The health effects of ground-level ozone and particulate matter (PM) is also cause for concern. Some studies suggest that long-term regular exposure to PM can increase your risk of early death and perhaps lung cancer. Studies on ozone show that once it gets into your lungs, it can continue to cause damage even when you feel fine. This is why the federal government, including Health Canada, is working to reduce the risks to your health.
Areas of particular concern for ozone in Canada are:
To reduce your exposure to smog and its potential health effects:
To help reduce the overall levels of smog in the air:
Health Canada's research on the health effects of smog played a role in the development of Canada-Wide Standards for particulate matter and ground-level ozone. Adopted in June 2000, these standards are an important step in reducing the effects of smog on our health.
Health Canada will continue to study the effects of short and long-term exposure to smog-producing pollutants. These studies will lead to more standards and guidelines to help protect Canadians against the effects of smog.
Additional It's Your Health articles. You can also call (613) 957-2991.
ę Her Majesty the Queen in Right of Canada,
represented by the Minister of Health, 2004
Updated: December 2003