Nitrogen Oxide Emissions

In 2010, nitrogen oxide (NO_x) emissions were 2060 kt, an increase of 36 kt (2%) from 2009 emission levels.

The level of NO_x emissions in 2010 was 441 (kt) (18%) lower than in 1990. The decline in NO_x emissions is attributable to two factors: a reduction in emissions from transportation, given the progressive introduction of cleaner technology and fuels for vehicles; and a reduction in emissions from electricity generation as a result of regulation and domestic/international agreements. The most recent decline (2007 to 2009) in NO_x emissions is attributable to a reduction in emissions from industrial sources (mainly the upstream petroleum industry), electric power generating plants and transportation. Reductions have been partially offset by emission increases from the oil and gas industry.

Nitrogen oxide emissions, Canada, 1990 to 2010

Note: Emissions from natural sources (e.g., forest fires) and open sources (e.g., prescribed burning) are not included in the indicator.
Source: Environment Canada (2012) National Pollutant Release Inventory: Air Pollutant Emissions Summaries and Trends.

Sources of nitrogen oxide emissions

Transportation (road, rail, air and marine) contributed most to Canada’s NO_x emissions, representing 33% (680 kt). The oil and gas industry and off-road vehicles emitted the next-largest proportions of national NO_x emissions, each representing 22% (458 kt).

Nitrogen oxide emissions by source, Canada, 2010

Note: Emissions from natural sources (e.g., forest fires) and open sources (e.g., prescribed burning) are not included in the indicator.
Source: Environment Canada (2012) National Pollutant Release Inventory: Air Pollutant Emissions Summaries and Trends.

Nitrogen oxide emissions by province and territory

Alberta was the province with the highest proportion of NO_xemissions, with 38% (787 kt) of national emissions (national emissions = 2061 kt). The upstream petroleum industry emitted the largest amount of NO_x for this province. Ontario contributed the second-largest proportion of NO_x, with 19% (383 kt) of national emissions. Quebec ranked third, with 12% (246 kt) of national emissions. In both Ontario and Quebec, transportation (e.g., cars, trucks, airplanes) and off-road vehicles were the most important sources of NO_x emissions.

Nitrogen oxide emissions by province and territory, Canada, 2010

Note: Emissions from natural sources (e.g., forest fires) and open sources (e.g., prescribed burning) are not included in the indicator.
Source: Environment Canada (2012) National Pollutant Release Inventory: Air Pollutant Emissions Summaries and Trends.

Nitrogen oxide emissions from industrial facilities

Environment Canada’s National Pollutant Release Inventory (NPRI) provides detailed information on air pollutant emissions from industrial facilities. The Canadian Environmental Sustainability Indicators (CESI) program provides access to this information through an online interactive map.

With the CESI interactive map, you can drill down to local areas and obtain details on NO_x emissions specific to reporting industrial facilities.

Source: Environment Canada (2012) National Pollutant Release Inventory: Facility Reported Data.

Related indicators

• National Air Pollutant Emissions