Ambient Levels of Nitrogen Dioxide

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Nitrogen dioxide (NO2) belongs to a group of nitrogen-containing substances called nitrogen oxides (NOx). Nitrogen oxides are emitted to the atmosphere from high-temperature combustion processes such as car engines, power plants and industrial processes. Although the majority of the emitted NOX is nitric oxide (NO), once in the air NO reacts with volatile organic compounds and ozone to form NO2. The major sources of NOX in Canada are on-road and off-road vehicles, the oil and gas industry, and the use of fuel for electricity generation and heating. Nitrogen dioxide plays an important role in the formation of ozone (O3) in the atmosphere. It is a precursor to fine particulate matter (PM2.5), and contributes to acid deposition and eutrophication. Nitrogen dioxide also has adverse health effects: it can irritate the lungs, decrease lung function, and increase susceptibility to allergens for people with asthma.

The annual average NO2 concentration indicators are based on the annual average of the NO2 daily concentrations.

National ambient level of nitrogen dioxide

In Canada, the annual average concentration of nitrogen dioxide (NO2)Footnote [1] in the air for 2013 was 9.2 parts per billion (ppb), or 1% lower than in 2012. The decreasing trend of 0.4 ppb per year was detected from 1999 to 2013 for the NO2 is consistent with the reduction in NOx emissions from cars and trucks as a result of the introduction of more stringent emissions standards by the federal government.

Nitrogen dioxide concentrations, Canada, 1999 to 2013

Line chart

Long description

The line chart shows the national annual average concentrations of nitrogen dioxide in the air in Canada from 1999 to 2013.

Data for this chart
Nitrogen dioxide concentrations, Canada, 1999 to 2013
YearAnnual average concentration
(parts per billion)
199915.0
200014.9
200114.2
200213.5
200313.7
200413.0
200512.6
200611.8
200711.4
200810.9
200910.4
20109.9
20119.7
20129.3
20139.2

Download data file (Excel/CSV; 682 B)

How this indicator was calculated

Note: The national annual average NO2 concentration indicator is based on the annual average of the daily concentrations recorded at 82 monitoring stations across Canada.
Source: Environment and Climate Change Canada (2015) National Air Pollution Surveillance (NAPS) program.

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Regional ambient levels of nitrogen dioxideFootnote [2]

Southern Quebec

In southern Quebec, the annual average concentration for nitrogen dioxide (NO2) for 2013 was 8.8 ppb, 5% lower than in 2012. The decreasing trend of 0.5 ppb per year detected from 1999 to 2013 is mostly attributable to the reduction in nitrogen oxide (NOx) emissions from cars and trucks, resulting from more stringent emissions standards.

Nitrogen dioxide concentrations, southern Quebec, 1999 to 2013

Line chart

Long description

The line chart shows the annual average concentrations of nitrogen dioxide in the air in southern Quebec from 1999 to 2013.

Data for this chart
Nitrogen dioxide concentrations, southern Quebec, 1999 to 2013
YearAnnual average concentration
(parts per billion)
199915.8
200014.9
200114.1
200213.0
200314.9
200413.3
200513.0
200611.3
200711.2
200811.7
200910.5
201010.6
201110.3
20129.3
20138.8

Download data file (Excel/CSV; 693 B)

How this indicator was calculated

Note: For southern Quebec, the annual average NO2 concentration indicator is based on the annual average of the daily concentrations recorded at 15 monitoring stations.
Source: Environment and Climate Change Canada (2015) National Air Pollution Surveillance (NAPS) program.

Southern Ontario

In southern Ontario, the annual average concentration of nitrogen dioxide (NO2) in the air for 2013 was 10.1 ppb, or 3% higher than in 2012. The decreasing trend of 0.7 ppb per year detected from 1999 to 2013 is mostly attributable to the reduction in nitrogen oxide (NOx) emissions from cars and trucks, resulting from more stringent emissions standards and to power plant closures and emission reduction measures.

Nitrogen dioxide concentrations, southern Ontario, 1999 to 2013

Line chart

Long description

The line chart shows the annual average concentrations of nitrogen dioxide in the air in southern Ontario from 1999 to 2013.

Data for this chart
Nitrogen dioxide concentrations, southern Ontario, 1999 to 2013
YearAnnual average concentration
(parts per billion)
199919.0
200018.7
200118.0
200217.2
200316.9
200415.9
200516.5
200614.0
200713.2
200812.7
200910.9
201010.9
201110.9
20129.7
201310.1

Download data file (Excel/CSV; 694 B)

How this indicator was calculated

Note: For southern Ontario, the annual average NO2 concentration indicator is based on the annual average of the daily concentrations recorded at 18 monitoring stations.
Source: Environment and Climate Change Canada (2015) National Air Pollution Surveillance (NAPS) program.

Prairies and northern Ontario

In the Prairies and northern Ontario, the annual average concentration of nitrogen dioxide (NO2) for 2013 was 8.1 ppb, or 1% higher than in 2012. The decreasing trend of 0.3 ppb per year detected from 1999 to 2013 is mostly attributable to the reduction in nitrogen oxide (NOx) emissions from cars and trucks, resulting from more stringent emissions standards.

Nitrogen dioxide concentrations, Prairies and northern Ontario, 1999 to 2013

Line chart

Long description

The line chart shows the annual average concentrations of nitrogen dioxide in the air in the Prairies and the northern Ontario from 1999 to 2013.

Data for this chart
Nitrogen dioxide concentrations, Prairies and northern Ontario, 1999 to 2013
YearAnnual average concentration
(parts per billion)
199912.8
200011.8
200111.2
200211.3
200311.6
200410.6
200510.0
20069.7
20079.6
20088.4
20099.1
20109.0
20118.5
20128.0
20138.1

Download data file (Excel/CSV; 717 B)

How this indicator was calculated

Note: For the Prairies and Northern Ontario, the annual average NO2 concentration indicator is based on the annual average of the daily concentrations recorded at 24 monitoring stations.
Source: Environment and Climate Change Canada (2015) National Air Pollution Surveillance (NAPS) program.

British Columbia

In British Columbia, the annual average concentration of nitrogen dioxide (NO2) in the air was 10.3 ppb in 2013, or 1% lower than in 2012. The decreasing trend of 0.3 ppb per year detected from 1999 to 2013 is mostly attributable to the reduction in nitrogen oxide (NOx) emissions from cars and trucks, resulting from more stringent emissions standards.

Nitrogen dioxide concentrations, British Columbia, 1999 to 2013

Line chart

Long description

The line chart shows the annual average concentrations of nitrogen dioxide in the air in British Columbia from 1999 to 2013.

Data for this chart
Nitrogen dioxide concentrations, British Columbia, 1999 to 2013
YearAnnual average concentration
(parts per billion)
199914.5
200015.6
200114.4
200214.0
200313.7
200413.6
200513.0
200613.2
200712.1
200811.9
200912.0
201010.2
20119.9
201210.3
201310.3

Download data file (Excel/CSV; 694 B)

How this indicator was calculated

Note: For British Columbia, the annual average NO2 concentration indicator is based on the annual average of the daily concentrations recorded at 22 monitoring stations.
Source: Environment and Climate Change Canada (2015) National Air Pollution Surveillance (NAPS) program.

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Ambient levels of nitrogen dioxide at monitoring stations

The National Air Pollution Surveillance (NAPS) program measures air pollutant concentrations at monitoring stations across Canada. The Canadian Environmental Sustainability Indicators (CESI) provide this information through an interactive indicator map. With the CESI interactive map, you can drill down to nitrogen dioxide (NO2) concentrations at specific monitoring stations.

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