What is the issue?

Canada's air quality is affected by pollutants that come from the combustion of fossil fuels in vehicles, homes, power plants, smelters, and other industries. Average air pollution levels in Canada have improved over the last 25 years, but smog remains a serious health concern in a number of highly populated parts of the country.

Smog can affect our health by irritating the eyes, nose, and throat, reducing lung capacity, and aggravating respiratory or cardiac diseases. It has also been implicated in premature deaths. Especially vulnerable are the elderly, children, and those with heart or lung disease. Recent studies suggest that there are no safe levels of human exposure to fine airborne particles and ground-level ozone, the two main air pollutants that make up smog. Government of Canada scientists have determined that air pollution results in tens of thousands of hospital and medical visits and over 5 000 premature deaths annually.

What do we know?

Air quality is assessed in terms of "good," "fair," and "poor" days based on the Index of the Quality of Air. A national assessment of air quality has shown general improvement since 1980. However, the number of fair and poor air quality days increased between 1995 and 1998 as a result of higher levels of ground-level ozone and fine airborne particles.

•  Download Number of days of fair and poor air Quality in Canada, 1980-98 (MS-Excel)  
• Number of days of fair and poor air Quality in Canada, 1980-98( HTML)

High ground-level ozone concentrations tend to peak during the spring and summer. The pollutant is a concern principally in the Windsor–Quebec City corridor and, to a lesser extent, in the southern Atlantic region and the Lower Fraser Valley of British Columbia. Although subject to annual variation, the overall trend for the number of days when ground-level ozone is of concern across these regions has been downward since the early 1980s. However, increases in high ground-level ozone days have occurred recently in the urbanized Windsor–Quebec City corridor between 1996 and 1998.

•  Download Levels of ground-level ozone, nitrogen dioxide, and sulphur dioxide in Canada, 1974-98 (MS-Excel)   
• Levels of ground-level ozone, nitrogen dioxide, and sulphur dioxide in Canada, 1974-98 (HTML)

Levels of PM₁₀—airborne particles less than 10 micrometres in size—tend to vary, depending on the region, the level of pollutant emissions from both local and long-range sources, and the season. However, high levels may occur in all seasons and affect most populated regions of Canada. These levels often occur during periods of high ozone, because the two contaminants share the same causal or precursor pollutants.

Although the trend shows that yearly average concentration of even finer particles (PM_2.5) decreased by about one-third from 1985 to 1998 for 11 Canadian cities in the PM_2.5 monitoring program, some of these Canadian cities continue to regularly record daily levels that are high enough to pose a health risk. Also, the yearly average concentration of PM_2.5 have risen recently, over the 1996–1998 period.

•  Download Levels of airborne particulate in Canada, 1974-98 (MS-Excel) 
•  Levels of airborne particulate in Canada, 1974-98HTML

The levels of the various pollutants in our air closely mimic the amounts emitted by numerous human activities. Thus, as emissions decrease, air quality improves. These emissions are tracked by the National Emissions Inventory of Criteria Air Contaminants. In 1995, the inventory reported nationwide emissions of 1.5 million tonnes of PM_2.5, 2.5 million tonnes of nitrogen oxides, 3.6 million tonnes of volatile organic compounds, 2.6 million tonnes of sulphur dioxide, and 17 million tonnes of carbon monoxide. The inventory also shows that the main sources of these pollutants are the fossil fuels used in vehicles, power plants, and industries, such as smelters.

What additional information do we need?

In order to succeed in addressing clean air issues, we need to expand what we know. For instance, we need:

• a better understanding of how pollutants change after they are released to the atmosphere;
• an improved understanding of how pollutants affect air quality, people, and the environment;
• more comprehensive and up-to-date information on air quality and emissions in order to track air pollution trends and advise Canadians of existing or potential air quality problems; and
• improved information on the mechanisms, costs, and potential benefits of preventing or controlling air pollution.

What are we doing based on the information we have?

Clean air requires an efficient approach involving actions and strategies that lead to reductions of many different pollutants at the same time. Reduced emissions of air pollutants not only will improve air quality but also will reduce the impacts of climate change and acid rain.

As part of a new approach to address smog under the Canada-wide Accord on Environmental Harmonization of the Canadian Council of Ministers of the Environment, new Canada-wide standards have been developed for PM_2.5 airborne particles and ground-level ozone. Federal, provincial, and territorial Ministers of the Environment agreed to these standards in June 2000. At the same time, they endorsed Joint Initial Actions related to smog, to be developed over the next five years.

In a joint effort, the federal and New Brunswick Environment departments have successfully pilot-tested a program to forecast certain ambient air pollutant levels and warn Canadians of impending smog episodes, and this work has been expanded to other provinces. To support this forecasting and other air research, the Government of Canada is investing in an expansion of the NAPS Network.

PM₁₀ airborne particles are being added, along with precursors of smog (sulphur dioxide, nitrogen oxides, volatile organic compounds, and ammonia), to the List of Toxic Substances under the Canadian Environmental Protection Act. A new agreement to significantly reduce the flow of pollutants across the border between Canada and the United States was brought into force in December 2000. To meet this commitment, the Government of Canada has announced a 10-year, $120.2 million investment in new measures to accelerate action on clean air, by focusing on cleaner vehicles and fuels, initial measures to reduce smog-causing emissions from industrial sectors, improvements to the NAPS Network and expansion of the public reporting by industry on pollutant releases.

In communities across Canada, Canadians are promoting clean air choices—alternative transportation, cleaner gasoline, and energy efficiency.

Further information

For more information on air quality issues, check the following*:

• Canadian Council of Ministers of the Environment:
  http://www.ccme.ca/
• Canadian Environmental Protection Act, 1999:
  www.ec.gc.ca/ceparegistry/
• Clean air:
  www.ec.gc.ca/air/menu_e.shtml
• Criteria Air Contaminants inventory and air quality trends:
  www.ec.gc.ca/pdb/ape/cape_home_e.cfm
• Fraser Valley:
  www.ecoinfo.org/env_ind/region/smog/smog.htm
• Montreal Urban Community:
  www.rsqa.cum.qc.ca/
• Ontario:
  www.airqualityontario.com
• Air Quality:
  www.ec.gc.ca/air_e.html#quality

*Note: Information found on some sites is presented only in the language in which it was written. We apologize for any inconvenience.