All official European Union website addresses are in the europa.eu domain.
See all EU institutions and bodiesDo something for our planet, print this page only if needed. Even a small action can make an enormous difference when millions of people do it!
Indicator Specification
Energy production and use accounts for the majority of nitrogen oxides (NOx) and sulphur dioxide (SO2) emissions, but only a small fraction of ammonia (NH3) emissions. These pollutants all contribute to acid deposition. Acidification is caused by emissions of sulphur dioxide, nitrogen dioxide and ammonia into the atmosphere, and their subsequent chemical reactions and deposition on ecosystems and materials. Deposition of acidifying substances causes damage to ecosystems, buildings and materials (corrosion). The adverse effect associated with each individual pollutant depends on its potential to acidify and the individual properties of the ecosystems and materials. The deposition of acidifying substance still often exceeds the critical loads of the ecosystems across Europe. Efforts to reduce the effects of acidification are therefore focused on reducing the emissions of acidifying substances. NOx and SO2 can react in the atmosphere and transform into small-diameter particulate matter which when inhaled, can have direct or indirect impacts on human health causing harmful effects such as respiratory problems. See EN07 for more information about energy-related particulate emissions. NOx is also a tropospheric ozone precursor that reacts in the atmosphere in the presence of sunlight to form ozone which, in high concentrations, can lead to significant health impacts and damage to crops and other vegetation (see also EN05). Furthermore, an excessive input of nitrogen nutrients from atmospheric deposition or via run-off following atmospheric deposition can lead to eutrophication of waters.
Emissions of SO2 and NOx (also NH3 where applicable) in 1000 tonnes.
Emissions kt
Several EU-wide emissions limits and targets exist for the reduction of total SO2, NOx and NH3 emissions, including the National Emissions Ceiling Directive (NECD; 2001/81/EC) and the UNECE LRTAP Convention Gothenburg Protocol under UNECE LRTAP Convention (UNECE 1999). This indicator provides relevant information for assessing the achievement of these targets and also for analyses performed within the European Commission’s Clean Air for Europe programme (CAFE). This thematic strategy on air quality was released in September 2005 (The CAFE Programme/implementation of the Thematic Strategy on Air Pollution, http://ec.europa.eu/environment/air/cafe/index.htm) and due to be reviewed by 2013.
The NEC Directive includes emission reduction targets that are slightly stricter than the targets set in the Gothenburg Protocol and requires the introduction of national emission ceilings for emissions of SO2, NOx and NH3 (and also for NMVOCs) in each Member State, as well as setting interim environmental objectives for reducing the exposure of ecosystems and human populations to damaging levels of the acid pollutants. Targets for the new Member States are temporary and are without prejudice to the on-going review of the NECD.
A proposal for a revised NEC Directive (which will set 2020 emission ceiling targets for these acidifying pollutants), is expected in 2013. Targets for Bulgaria and Romania are provisional and not binding. Hence, the existing EU25 NECD Target has been used in the following analysis.
In terms of the energy sector, the most relevant NEC Directive targets for the EU-25 (exclude Romania and Bulgaria) as a whole are:
NH3 emissions are also an important source of acid deposition and have an emissions target under NEC (emissions reduction target of 15 % by 2010 from 1990 levels), but energy-related emissions of ammonia are insignificant, accounting for only 2.5 % of total EU-27 ammonia emissions in 2005. Agriculture is by far the largest contributing sector to EU ammonia emissions.
Other key policies that have contributed to the reduction of acidifying emissions across Europe include:
Emissions of NOx, SO2 and NH3 are covered by the NECD and the Gothenburg Protocol to the UNECE LRTAP Convention. Both instruments contain emission ceilings (limits) that countries must meet by 2010. See CSI001
Indicator is based on officially reported national total and sectoral emissions to UNECE/EMEP (United Nations Economic Commission for Europe/Co-operative programme for monitoring and evaluation of the long-range transmission of air pollutants in Europe) Convention on Long-range Transboundary Air Pollution (LRTAP Convention), submission 2010. Recommended methodologies for emission inventory estimation are compiled in the EMEP/CORINAIR Atmospheric Emission Inventory guidebook, EEA Copenhagen (EEA, 2009). Base data are available from the EEA Data Service (http://dataservice.eea.europa.eu/dataservice/metadetails.asp?id=1096) and the EMEP web site (http://www.ceip.at/). Recalculations of Member States data may happen. These are fully documented in the EEA report http://www.eea.europa.eu/publications/eu-emission-inventory-report-1990-2009.
Base data, reported in NFR are aggregated into the following EEA sector codes to obtain a common reporting format across all countries and pollutants:
The following table shows the conversion of Nomenclature for Reporting (NFR) sector codes used for reporting by countries into EEA sector codes:
EEA classification |
Non-GHGs (NFR) |
GHG (CRF) |
National totals |
National total |
National totals without LUCF |
Energy Industries |
1A1 |
1A1 |
Fugitive emissions |
1B1, 1B2 |
1B |
Road transport |
1A3b |
1A3b |
Non-road transport (non-road mobile machinery) |
1A3 (exl 1A3b) |
1A3a, 1A3c, 1A3d, 1A3e |
Industrial processes |
2 |
2 |
Other non-energy (Solvent and product use) |
3, 7A |
3 |
Agriculture |
4 |
4 |
Waste |
6 |
6 |
Household and services |
1A4ai, 1A4aii, 1A4bi, 1A5a |
1A4A, 1A4B |
Manufacturing / Construction |
1A2 |
1A2 |
Officially reported data following agreed procedures and Emission Inventory Guidebook (EEA 2009), e.g. regarding source sector split. The incomplete reporting and resultant extrapolation may obscure some trends.
The uncertainties of total sulphur dioxide emission estimates in Europe are relatively low, as the sulphur emitted mainly comes from the fuel burnt and therefore can be accurately estimated. However, because of the need for interpolation to account for missing data the complete dataset used here will have higher uncertainty. EMEP has compared modelled (which include emission data as one of the model parameters) and measured concentrations throughout Europe (EMEP 2005). From these studies the uncertainties associated with the modelled annual averages for a specific point in time have been estimated in the order of ± 30 %. This is consistent with an inventory uncertainty of ±10 % (with additional uncertainties arising from the other model parameters, modelling methodologies, and the air quality measurement data etc). In contrast, NOx emission estimates in Europe are thought to have higher uncertainty, as the NOx emitted comes both from the fuel burnt and the combustion air and so cannot be estimated accurately from fuel nitrogen alone. EMEP has compared modelled and measured concentrations throughout Europe (EMEP 2005). From these studies differences for individual monitoring stations of more than a factor of two have been found. This is consistent with an inventory of national annual emissions having an uncertainty of ±30% or greater (there are also uncertainties in the air quality measurements and especially the modelling). For some countries, reported time-series emissions data may be inconsistent. This may occur where for example different inventory reporting definitions have been used in different years and/or where changes made to estimation methodologies have not been applied back to 1990. For all emissions the trend is likely to be much more accurate than individual absolute annual values - the annual values are not independent of each other.
No uncertainty has been specified
Work specified here requires to be completed within 1 year from now.
Work specified here will require more than 1 year (from now) to be completed.
For references, please go to https://www.eea.europa.eu/data-and-maps/indicators/specification.2010-08-10.4640130926-2 or scan the QR code.
PDF generated on 28 Mar 2024, 06:42 PM
Engineered by: EEA Web Team
Software updated on 26 September 2023 08:13 from version 23.8.18
Software version: EEA Plone KGS 23.9.14
Document Actions
Share with others