International comparison: air pollutant emissions in selected countries

Sulphur oxides

Key results

In 2019, Canada:

• saw a decrease of 50% in sulphur oxides (SO_X) emissions from 2009 levels
• ranked fourth highest in SO_X emissions among OECD member countries
• had the third highest ratio of SO_X emissions to gross domestic product among the top 10 emitting OECD member countries

Sulphur oxides emissions and emissions intensity of the top 10 emitting member countries of the Organisation for Economic Co-operation and Development, 2009 and 2019

How this indicator was calculated

Note: Definitions of pollution sources and estimation methods may differ from country to country. Comparisons should be made with caution. Gross domestic product values are in millions of constant United States dollars, constant purchasing power parity, for the base year 2010. The use of purchasing power parity facilitates international comparison of gross domestic product by creating an equivalent purchasing power basis for each country compared.
Source: Organisation for Economic Co-operation and Development (2021) OECD.Stat.

Although Canada's SO_X emissions declined by 692 kilotonnes from 2009 to 2019, Canada ranked as one of the highest emitters among OECD member countries, behind Turkey, Australia and the United States. Of the top 10 emitters, the United States experienced the largest decrease (6 362 kilotonnes, or 78%), driven by reduced emissions from the coal-fired electricity production industry.

All of the top 10 emitting member countries experienced declines in emissions between 2009 and 2019.

In terms of the ratio of SO_X emissions to gross domestic product, all top 10 emitting member countries reported declines ranging between 34% and 82% from 2009 to 2019.

Note that, in 2009, South Korea was the 10th highest in SO_X emissions among OECD member countries with 388 kilotonnes. Since no data was available for 2019, South Korea is not represented in the comparison as the top 10 emitting countries are based on 2019 emissions.

Nitrogen oxides

Key results

In 2019, Canada:

• saw a decrease of 15% in nitrogen oxides (NO_X) emissions from 2009 levels
• ranked third highest in NO_X emissions among OECD member countries
• had the second highest ratio of NO_X emissions to gross domestic product among the top 10 emitting OECD member countries

Nitrogen oxides emissions and emissions intensity of the top 10 emitting member countries of the Organisation for Economic Co-operation and Development, 2009 and 2019

How this indicator was calculated

Note: Definitions of pollution sources and estimation methods may differ from country to country. Comparisons should be made with caution. Gross domestic product values are in millions of constant United States dollars, constant purchasing power parity, for the base year 2010. The use of purchasing power parity facilitates international comparison of gross domestic product by creating an equivalent purchasing power basis for each country compared.
Source: Organisation for Economic Co-operation and Development (2021) OECD.Stat.

In 2019, Canada ranked as one of the highest emitters among OECD member countries, behind the United States and Australia, despite a reduction of 300 kilotonnes in NO_X emissions between 2009 and 2019. Of the top 10 emitting members, the United States experienced the largest reduction over that period (6 458 kilotonnes, or 45%). In 2019, emissions in Australia were 21% higher than in 2009.

Emissions intensity, the ratio of NO_X emissions to gross domestic product, was lower in 2019 than it was in 2009 for all top 10 emitting member countries. The reductions in intensity were between 4% and 57%.

Note that, in 2009, South Korea was the ninth highest in NO_X emissions among OECD member countries with 1 014 kilotonnes. Since no data was available for 2019, South Korea is not represented in the comparison as the top 10 emitting countries are based on 2019 emissions.

Carbon monoxide

Key results

In 2019, Canada:

• saw a decrease of 18% in carbon monoxide (CO) emissions from 2009 levels
• ranked second highest in CO emissions among OECD member countries
• had the highest ratio of CO emissions to gross domestic product among the top 10 emitting OECD member countries

Carbon monoxide emissions and emissions intensity of the top 10 emitting member countries of the Organisation for Economic Co-operation and Development, 2009 and 2019

How this indicator was calculated

Note: Definitions of pollution sources and estimation methods may differ from country to country. Comparisons should be made with caution. Gross domestic product values are in millions of constant United States dollars, constant purchasing power parity, for the base year 2010. The use of purchasing power parity facilitates international comparison of gross domestic product by creating an equivalent purchasing power basis for each country compared.
Source: Organisation for Economic Co-operation and Development (2021) OECD.Stat.

In 2019, the United States was the highest CO emitting country, followed by Canada. The top 10 emitting member countries of the OECD experienced declines in emissions between 2% and 53% in 2019 from 2009 levels.

Except for Japan, declines were also observed in the ratio of CO emissions to gross domestic product between 2009 and 2019; they ranged from 12% to 73% for the top 10 emitting countries.

Note that, in 2009, Chile was the third highest in CO emissions among OECD member countries with 4 718 kilotonnes. Since no data was available for 2019, Chile is not represented in the comparison as the top 10 emitting countries are based on 2019 emissions. 

Volatile organic compounds

Key results

In 2019, Canada:

• saw a decrease of 15% in volatile organic compounds (VOC) emissions from 2009 levels
• ranked second highest in VOC emissions among OECD member countries
• had the second highest ratio of VOC emissions to gross domestic product among the top 10 emitting OECD member countries

Volatile organic compounds emissions and emissions intensity of the top 10 emitting member countries of the Organisation for Economic Co-operation and Development, 2009 and 2019

How this indicator was calculated

Note: Definitions of pollution sources and estimation methods may differ from country to country. Comparisons should be made with caution. Gross domestic product values are in millions of constant United States dollars, constant purchasing power parity, for the base year 2010. The use of purchasing power parity facilitates international comparison of gross domestic product by creating an equivalent purchasing power basis for each country compared.
Source: Organisation for Economic Co-operation and Development (2021) OECD.Stat.

Although Canada's VOC emissions declined by 296 kilotonnes between 2009 and 2019, Canada ranked as one of the highest emitters among the member countries of the OECD, behind the United States. Most of the top 10 emitting member countries experienced declines in emissions between 2009 and 2019, with the exception of Turkey whose emissions increased by 3%.

The reductions in emissions intensity range from 23% to 42% between 2009 and 2019 for the top 10 emitting member countries.

Note that, in 2009, Chile was the second highest in VOC emissions among OECD member countries with 2 381 kilotonnes. Since no data was available for 2019, Chile is not represented in the comparison as the top 10 emitting countries are based on 2019 emissions. 

Fine particulate matter

Key results

In 2019, Canada:

• saw an increase of 21% in fine particulate matter (PM_2.5) emissions from 2009 levels
• ranked second highest in PM_2.5 emissions among OECD member countries
• had the highest ratio of PM_2.5 emissions to gross domestic product among OECD member countries

Fine particulate matter emissions and emissions intensity of the top 10 emitting member countries of the Organisation for Economic Co-operation and Development, 2009 and 2019

How this indicator was calculated

Note: Definitions of pollution sources and estimation methods may differ from country to country. Canada and the United States include open sources such as dust from roads, prescribed forest burning and agriculture in their PM_2.5 emissions. These sources are not always reported by other OECD member countries. Comparisons should be made with caution. Gross domestic product values are in millions of constant United States dollars, constant purchasing power parity, for the base year 2010. The use of purchasing power parity facilitates international comparison of gross domestic product by creating an equivalent purchasing power basis for each country compared.
Source: Organisation for Economic Co-operation and Development (2021) OECD.Stat.

Canada and Turkey experienced an increase in PM_2.5 emissions in 2019 from 2009 levels, by 273 and 8 kilotonnes respectively. Despite these increases in emissions, all the top 10 member countries experienced declines in their emissions intensity, which varied between 3% and 42%, from 2009 to 2019.

Canada and the United States include open sources^{Footnote 1}  such as dust from roads, prescribed forest burning and agriculture in their PM_2.5 emissions. These sources are not always reported by other OECD member countries.

Note that, in 2009, Chile was the third highest in PM_2.5 emissions among OECD member countries with 381 kilotonnes. Since no data was available for 2019, Chile is not represented in the comparison as the top 10 emitting countries are based on 2019 emissions.

At the time of this update the OECD.Stat database contained emissions data up to the end of 2019, reflecting delays in the collection and aggregation of international data. Data are collected for each member country from the following sources:

• the Centre on Emission Inventories and Projections database (as of August 2021) of the Convention on Long-Range Transboundary Air Pollution
• the National Inventory Submissions 2021 (as of August 2021) of the United Nations Framework Convention on Climate Change
• the replies to the OECD Questionnaire on the State of the Environment and comments from member countries received before late August 2021
• national data from specific countries

The OECD.Stat database indicates the source used to report emissions for each country, pollutant and year.

Air pollutant emissions indicators

Emissions for each member country are estimated or measured using one or several of the following methods:

• continuous emission monitoring systems
• predictive emission monitoring
• source testing
• mass balance
• site-specific emission factors
• published emission factors
• engineering estimates
• special studies

Generally, each country compiles and estimates its air pollutant emissions combining facility-level emissions (aka point sources) with sector-level emissions (or area sources).

Canada's data are derived from the annual Convention on Long-Range Transboundary Air Pollution submission to the Centre on Emission Inventories and Projections database. The submitted air pollutant emission data are based on Canada's Air Pollutant Emission Inventory. This includes information reported by facilities to the National Pollutant Release Inventory as well as emission estimates compiled for non-reporting facilities, non-reporting sources such as motor vehicles or non-reported pollutants (in-house emissions estimates).

Air pollution emissions per unit of gross domestic product

The emissions intensity indicators are expressed in tonnes of pollutants emitted per million United States dollars using constant gross domestic product at purchasing power parity for the base year 2010. Purchasing power parity is a weighted average of the relative prices, quoted in national currency, of comparable items between countries. Using purchasing power parity facilitates international comparison of gross domestic product by creating an equivalent purchasing power basis for each country compared.

Countries included in the comparison

The indicators include all member countries of the OECD as of September 2021. The data presented in the indicator reflect data completeness in the OECD.Stat database at the time of reporting.