Air Quality The air quality indicators reflect the potential for long-term exposure of Canadians to ground-level ozone and PM2.5, key components of smog and two of the most common and harmful air pollutants to which people are exposed. Both the ozone and PM2.5 indicators are population-weighted estimates of average warm-season concentrations of these pollutants observed at monitoring stations across Canada.
	Greenhouse Gas Emissions The greenhouse gas emissions indicator tracks the annual releases of the six greenhouse gases that are the major contributors to climate change. The indicator comes directly from the greenhouse gas inventory report prepared by Environment Canada for the United Nations Framework Convention on Climate Change (UNFCC).
	Freshwater Quality The freshwater quality indicator reports the status of surface water quality at selected monitoring sites across the country, including the Great Lakes and, for the first time, northern Canada. The indicator uses the Water Quality Index (WQI), endorsed by the Canadian Council of Ministers of the Environment (CCME)1, to summarize the extent to which water quality guidelines for the protection of aquatic life (plants, invertebrates and fish) are exceeded in Canadian rivers and lakes.

Canadians’ health and their social and economic well-being are fundamentally linked to the quality of their environment. Recognizing this, in 2004, the Government of Canada committed to reporting annually on national indicators of air quality, greenhouse gas emissions and freshwater quality.

These indicators were first reported in the Canadian Environmental Sustainability Indicators 2005 report and have been updated and further developed in this year’s report.

Environment Canada, Statistics Canada and Health Canada are working together to further develop and report on these indicators. Reflecting the joint responsibility for environmental management in Canada, this effort has benefited from the cooperation and input of the provinces and territories.

The individual indicators continue to be developed, with increasingly robust analyses to track changes. Improvements are being implemented to make the indicators more understandable, relevant and useful to decision-makers and the public. They will benefit in the future from better environmental monitoring, new scientific knowledge and guidelines, improved data management and better analytical methods. New surveys of business and household actions affecting the environment will provide information to assist in interpreting the indicator trends. Online tools are being developed that will enable users to examine regional and sectoral details and conduct their own analyses.