Emissions of nitrogen oxides have fallen by 62 per cent between 1990 and 2010, and fell by 3 per cent between 2009 and 2010. Emissions in 2010 were 5 per cent below the lowest international target for the UK.

The UK has met current international targets set in the National Emission Ceilings Directive (NECD) and the Gothenburg Protocol under the Convention on Long Range Transboundary Air Pollution (CLRTAP) to reduce total emissions by 2010.

 Emissions of nitrogen oxides (NOx) and targets: UK, 1970 – 2010

• Emissions of nitrogen oxides (NOx) are 62 per cent lower than 1990 levels, compared with the 2010 target of 56 per cent reduction the UNECE Gothenburg Protocol and the EU National Emissions Ceiling Directive (NECD).
• Ammonia emissions (excluding natural emissions from wild animals and humans) fell  by 21 per cent between 1990 and 2010 to 284 thousand tonnes,  compared with the 2010 target of 297 thousand tonnes under the UNECE Gothenburg Protocol and the EU National Emissions Ceiling Directive.
• A large increase in road traffic accounts for the steep climb in emissions between 1984 and 1989, and road transport still accounts for around one third of total emissions
• Catalytic converters fitted to vehicles and stricter regulations have resulted in a strong downward trend since 1990, particularly from road transport and power stations.

Why is this important –Nitrogen oxides are acidifying and eutrophying gases and give rise to ground-level ozone. 

Acidification is the process where chemical reactions involving air pollutants create acidic compounds which can cause harm to vegetation and buildings (including as acid-rain).

Eutrophication is the process where nitrogen is deposited in soils or in rivers and lakes through rain and affects the nutrient levels and diversity of species in sensitive environments, for example encouraging algae growth in lakes and water courses.

Ground-level ozone arises where chemical reactions involving air pollutants create the toxic gas ozone (O3) which can affect people’s health and can damage wild plants, crops, forests and some materials.

This pollutant can also react in the atmosphere to form secondary particulate matter (PM), which can adversely impact human health. Chronic exposure to PM can contribute to the risk of developing cardiovascular and respiratory diseases.

 Data download

The key facts publication contains a downloadable version of this page
Next scheduled update December 2012
Additional data and information on emissions of nitrogen oxides
Air pollutant emissions methodology
Government policy on air quality
Air quality in Wales, Scotland and Northern Ireland
Emissions of air pollutants in Europe