The Canadian Environmental Sustainability Indicators CESI program provides data and information to track Canada's performance on key environmental sustainability issues. The International Comparison of Air Pollutant Emissions indicators track air pollutant emissions for Canada and nine other leading economies G8 countries plus Australia and Sweden . Four pollutants were selected for these indicators, including: sulphur oxides, nitrogen oxides, volatile organic compounds and ammonia. Emissions are reported in kilotonnes. A country's air pollutant emissions intensity for the same four pollutants was also provided in terms of total tonnes of emissions per unit of gross domestic product GDP in million US$ . The GDP used is in American dollars US$ , at constant prices, and constant purchasing power parity, for the base year of 2005. Information is provided to Canadians in a number of formats including: static and interactive maps, charts and graphs, HTML and CSV data tables and downloadable reports. See supplementary documentation for data sources and details on how those data were collected and how the indicator was calculated.