Air is a mixture of gases that surrounds the earth and makes up our atmosphere. Pure air consists of 21% oxygen and 78% nitrogen by volume, plus traces of other gases such as argon, carbon dioxide and water vapour.
The air we breathe is not pure. It may contain thousands of chemical and biological substances emitted into the atmosphere by natural sources (e.g. forest fires) or human activities. In addition, these chemicals may react in the atmosphere to produce other pollutants. Substances that foul the air are called pollutants which include ground-level ozone (O3), particulate matter (PM), sulphur dioxide (SO2), carbon monoxide (CO), nitrogen oxide (NOx), volatile organic compounds (VOCs), hydrogen sulphide (H2S), sulphates and nitrates. Additional air pollutants of concern include toxic metals (lead, mercury, manganese, arsenic and nickel), benzene, formaldehyde, polychlorinated biphenyl's (PCB), dioxins, and other persistent organic compounds.
Particles and gases in the air can be a source of lung irritation. Chronic exposure to pollutants in the air we breathe can damage deep portions of the lung even after symptoms such as coughing or a sore throat disappear. Ozone damages the alveoli (individual air sacs in the lung where oxygen and carbon dioxide are exchanged). The health effects of air pollution can be seen as a pyramid.
Do whatever you can to reduce your exposure to air pollution. Refer to radio or television weather reports or your local newspaper for information about air quality. On days when the ozone (smog) level is unhealthy, restrict your outdoor physical activity to early morning or evening because smog is increased in sunlight. When pollution levels are dangerous, limit outdoor activities as necessary. To have a long-term impact on air pollution levels, adjust your lifestyle to decrease pollution emissions: drive less, consume less energy and make wise choices as a consumer.
The young, elderly and sensitive populations with existing conditions of either cardiovascular disease or respiratory disorders such as asthma, emphysema, chronic bronchitis or allergy problems, are the most widely affected by poor air quality.
People with chronic heart and lung disease should avoid stenuous outdoor activity on smoggy days.
Fossil fuel use produces two main greenhouse gases (GHGs): carbon dioxide (CO2) and methane (CH4), neither of which directly cause air pollution. However, fossil fuel use also produces other by-products which do cause air pollution, such as smog. The combustion of fossil fuel is the largest contributor to both air pollution and climate change. Reductions in the consumption of fossil fuels (gasoline, diesel, coal) would provide health benefits for the Canadian population.
Another link between these two problems is that increasing temperatures anticipated with climate change could serve to magnify the effects of pollutants already in the air. Projections of more frequent and severe heat waves and humidity could lead to increases in smog and air pollution advisories. Increases in pollens and mold spores could compound the situation and affect those with cardiovascular disease, respiratory disorders such as asthma, emphysema and chronic bronchitis, and allergy problems. Trees and other vegetation that give rise to allergenic pollens grow more profusely in a warmer climate. When combined with smog and other atmospheric pollutants, illness from allergic respiratory disease, particularly asthma, could increase.
Indoor air quality is important to human health because we spend nearly 90 % of our time indoors. Occupants of indoor environments may be exposed to a variety of pollutants originating from human activities; combustion from heating and cooking, consumer products, furnishings, building materials and outdoor air. The quality of indoor air depends both on the quality of outdoor air and on the strength of emissions of indoor sources. In most inhabited spaces there is a continuous exchange of air with the outside. Therefore, all contaminants of outdoor air are likely to be present indoors except ozone which reacts with the surfaces of objects within a house and is thus greatly reduced in concentration.
Governments, industry, communities and individual Canadians are working together on a number of initiatives to control air pollution. One of these initiatives is the development of Canada-Wide Standards for particulate matter and ground-level ozone. These Standards adopted in June 2000 have target dates and implementation plans agreed to by all governments in Canada, and should help to reduce the levels of air pollution to which Canadians are exposed. In addition, the federal government recently announced additional measures for reducing cross-border transport of pollutants under provisions of the Canada/US Air Quality Accord.
A new regulation on sulphur in gasoline has also recently been introduced, which will provide significant improvements in air quality with resultant health benefits for all Canadians. The federal government is also presently conducting risk assessments for alternate additives and fuels to determine the benefits that might be realized. Other measures to reduce the impact of transportation and fossils fuels are currently being examined.
At a wider international level, Canada has been working for the past 15 years through the United Nations, to considerably reduce emissions of environmental pollutants under a variety of national laws, international agreements, and voluntary initiatives. As part of such initiatives, Canada signed the 1998 Kyoto Protocol to the United Nations Framework Convention on Climate Change. It commits Canada and other countries to significant reductions in their emissions of greenhouse gases such as carbon dioxide, which result from the combustion of fuels.
Canada will continue its research efforts on the health effects of air pollution, in order to obtain the scientific and medical evidence needed to support further measures to protect and improve the health of Canadians. We will also continue to work closely with both governmental and non-governmental organizations, to ensure that accurate information on health risks from pollution is available to all Canadians, and to reduce these health risks as much as possible.
Vehicles are the principal source of urban air pollution in Canada.
Leave your car at home: walk, cycle or use public transit.
If you do drive, there are many ways to reduce emissions and conserve fuel:
Our homes consume vast quantities of energy and contribute to air pollution in many ways: