Sulphur and nitrogen emissions

Atmospheric pollutants from energy transformation and energy consumption, but also from industrial processes, are the main contributors to regional and local air pollution and raise concerns as to their effects on human health and ecosystems.

In the atmosphere, emissions of sulphur and nitrogen compounds are transformed into acidifying substances. When these substances reach the ground, acidification of soil, water and buildings arises. Soil acidification is one important factor causing forest damage; acidification of the aquatic environment may severely impair the life of plant and animal species.

Nitrogen oxides (NOX) also contribute to ground-level ozone formation and are responsible for eutrophication, reduction in water quality and species richness. High concentrations of NOX cause respiratory illnesses.


Total emissions refer to emissions from human activities of sulphur oxides (SOX) and nitrogen oxides (NOX).

It should be kept in mind that SOX and NOX emissions provide only a partial view of air pollution problems. They should be supplemented with information on the acidity of rain and snow, and the exceedance of critical loads in soil and water, which reflect the actual acidification of the environment, and with information on population exposure to air pollutants.


International data on SOX and NOX emissions are available for almost all OECD countries. The details of estimation methods for emissions such as emission factors and reliability, extent of sources and pollutants included in estimation, etc., may differ from one country to another.

The high emission levels of SOX for Iceland are due to SOX emissions from geothermal energy which represented 80% of total emissions in 2012.

OECD totals do not include Chile and Mexico.


SOX emissions have continued to decrease since 2000 for the OECD as a whole as a combined result of changes in energy demand through energy savings and fuel substitution, pollution control policies and technical progress.

NOX emissions have continued to decrease in the OECD overall since 2000, but less than SOX emissions. This is mainly due to changes in energy demand, pollution control policies and technical progress. In the late 2000s, the slowdown in economic activity following the 2008 economic crisis further contributed to reduce emissions. However, these results have not compensated in all countries for steady growth in road traffic, fossil fuel use and other activities generating NOX.


Further information

Online databases


Table. Sulphur and nitrogen oxides emissions

Sulphur and nitrogen oxides emissions
Kilograms per capita, 2012 or latest available year