Air pollution

What is air pollution?

Air pollution is mainly composed of gas and particulate matter (PM). The main gases that contaminate the air are ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and carbon monoxide (CO). PM can be classed according to size: PM of less than 10 micrometers (PM₁₀) and PM of less than 2.5 micrometers (PM_2.5). The smaller particles can penetrate deep into the lungs.

The main air contaminants come from sources like motor vehicles, industrial processes, heating (oil, wood, propane, etc.), and forest fires. These contaminants can be harmful to health and the environment. They are typically used as air quality indicators and are subject to continuous monitoring by provincial and federal agencies.

Smog

Smog is a common phenomenon that manifests itself as a yellow haze, reducing visibility. It is the result of a mixture primarily composed of fine particles (PM_2.5) and ozone, more specifically known as tropospheric ozone, because it is measured at ground level.

Smog can form at any time of the year. In summer, it is largely made up of ozone and fine particles, whereas in the winter it is mostly composed of particles. Smog episodes can last several hours or days, and sometimes as much as a week or more. Their intensity depends on certain meteorological conditions (sunshine, temperature, and wind), the time of day, the season, and pollution sources. We can be exposed to smog both in urban and rural environments.

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How can air pollution affect my health?

Air contaminants are associated with adverse health effects, especially as concerns respiratory and cardiovascular function. The effect that pollution has on health is determined by exposure time, concentration of the pollutants and the health status of the persons exposed.

The most common symptoms associated with short-term exposure to pollution (a few minutes to a few days) are:

• Irritation of the respiratory tract (cough, irritated throat);
• Wheezing
• Tightness in the chest
• Pain while deep breathing
• Difficulty breathing

In the scientific literature, a daily increase in air contaminant concentrations is associated with an increase in acute respiratory symptoms and bronchitis cases, as well as a rise in emergency room visits and hospital admissions for cardiorespiratory problems.

Moreover, recent studies show that prolonged exposure to air contaminants (a few months to a few years) can have adverse effects on lung capacity, lung development in children, and reproduction (complications during pregnancy, low birth weight, and premature births). Also, the link between long-term exposure to fine particles and mortality has particular implications for persons living with diabetes, chronic pulmonary obstructive disease, heart failure, and inflammatory diseases such as rheumatoid arthritis and lupus.

Compared with other factors such as smoking, air pollution represents a relatively low health risk. However, in terms of public health, the impact of pollution is non-negligible since a large number of people are exposed to air pollution on a daily basis.

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Am I vulnerable to air pollution?

A number of factors influence your vulnerability to air pollution, in particular

• The type of air pollution that you are exposed to in your living environments
• Your level of exposure to pollutants
• Your health status, age, genetic predisposition, and lifestyle (for example, smoking)

Although nobody is immune to the health effects of air pollution, certain people may be more sensitive and at increased risk:

• Children, since their respiratory system is not fully developed
• People with respiratory problems (asthma, chronic bronchitis, emphysema, etc.)
• Persons who have or have had cardiovascular problems (angina, myocardial infarction) or who have heart failure, arrhythmia, or other heart conditions
• des personnes souffrant ou ayant souffert de problèmes cardiovasculaires (angine, infarctus du myocarde) ou qui souffrent d’insuffisance cardiaque, d’arythmie ou d’autres affections cardiaques
• Athletes and people who work outdoors, especially when they work/play during periods of high contamination or live in polluted areas (i.e., motor vehicle traffic, industrial zones, etc.).

Even if none of these groups describe you and you are in good health, you can still be affected by poor air quality and may sometimes feel symptoms such as

• Eye irritation
• Increased nasal or throat secretions
• Cough
• Respiratory difficulties, especially during exercise

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How can air quality be improved?

Both citizens and businesses can help reduce pollution. Using public transit, carpooling, and walking are among the ways to achieve this objective. Motorists are encouraged to avoid letting their engines idle uselessly while stopped.

In the winter, wood heating is a significant source of pollution in many cities and neighborhoods. People with more than one heat source should avoid using their slow-burning stoves or their fireplaces during periods of poor air quality.

Industries are also encouraged to use cleaner fuels, even if they are already subject to various regulations, in particular regarding the emission of chemical substances.