Indicator Assessment

Emissions of the main air pollutants in Europe

Indicator Assessment
Prod-ID: IND-366-en
  Also known as: CSI 040 , AIR 005
Published 01 Jun 2015 Last modified 11 May 2021
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  • Anthropogenic emissions of the main air pollutants decreased significantly in most EEA-33 member countries between 1990 and 2012:
    • Nitrogen oxides (NOX) emissions decreased by 46% (51% in the EU-28);
    • Sulphur oxides (SOX) emissions decreased by 75% (84% in the EU-28);
    • Non-methane volatile organic compounds (NMVOC) emissions decreased by 56% (60% in the EU-28);
    • Ammonia (NH3) emissions decreased by 24% (28% in the EU-28); and
    • Fine particulate matter (PM2.5) emissions decreased by 35% (35% in the EU-28).
  • The EU-28 as a whole did not meet its 2010 target to reduce emissions of NOX. A further reduction of 2.2% from the 2010 emissions level is required to meet the interim environmental objectives set in the European Union’s 2001 National Emission Ceiling Directive (NECD).
  • The EU-28 met its continuing obligation to maintain emissions of SOX, NH3 and NMVOC below legally binding targets as specified by the NECD. A number of EU Member States reported emissions above their NECD emission ceilings: nine for NOX, three for NH3, and one for NMVOCs. There are no emission ceilings for primary PM2.5.
  • Three additional EEA member countries have emission ceilings for 2010 set in the Gothenburg Protocol under the 1979 UNECE Convention on Long-range Transboundary Air Pollution (Liechtenstein, Norway and Switzerland). All three countries met the SOx ceiling. Switzerland also met the ceilings for the other three pollutants. Liechtenstein exceeded the NMVOC ceiling. Norway breached two ceilings, for NH3 and for NOx.

The National Emission Ceilings Directive (NECD) and the Gothenburg Protocol under the Convention on Long-range Transboundary Air Pollution (LRTAP Convention) set emission ceilings for European countries for sulphur oxides (SOx), nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOC), and ammonia (NH3). The NECD emission ceilings had to be met by 2010, and maintained at levels lower than the ceilings for all subsequent years. The 2012 amended Gothenburg Protocol sets 2010 ceilings for these four pollutants and for 2020 it also includes ceilings for primary fine particulate matter (PM2.5) emissions (see indicator Specification for details).

The aim of the NECD and the Gothenburg Protocol is to restrict emissions of air pollutants, also including ozone and particulate matter (PM) precursors or those that contribute to ecosystem acidification and eutrophication. Information on the exceedance of air quality standards for the protection of human health and the exposure of ecosystems to acidification, eutrophication and ozone is available from the EEA indicators CSI004 and CSI005, respectively.

Nitrogen oxides (NOx)

NOx emissions for the EEA-33 and the EU-28 continue to fall, and are about half of their value in 1990. This reduction has primarily been due to the introduction of three way catalytic converters for cars. However the observed emissions reductions from some of the more modern vehicles have not met initial expectations and actual emissions from vehicles (often termed ‘real-world driving emissions’) may exceed those emissions during the test-cycle as specified in the European emission standards for each vehicle type.

Sulphur oxides (SOx)

In 2012, SOx emissions were approximately 15% of their 1990 levels for the EU-28. Emissions continue to fall, and for the EEA-33 they are approaching a quarter of the 1990 emissions. All countries have met their 2010 emission ceiling commitments.

Non-methane volatile compounds (NMVOC)

NMVOC emissions for the EEA-33 and the EU-28 have fallen to less than half their 1990 levels, and nearly all countries have reported emissions below their 2010 emission ceilings.

Ammonia (NH3)

NH3 emissions have fallen less than those of the other NECD pollutants. They fell by about a quarter from their value in 1990 for both the EEA-33 and the EU-28. The vast majority of countries have reported meeting their NECD 2010 emission ceiling commitments. The NECD does not include a stricter ceiling for environmental objectives, as in the case of the other main air pollutants.

Particulate matter (PM2.5)

Emissions of primary PM2.5 have reduced by about a third for both the EEA-33 and the EU-28 compared to their levels in 1990. More importantly the timeline of emissions reductions shows that the EEA-33 as a whole is on track towards achieving the total reduction target implied by the Gothenburg Protocol. However, country-specific PM2.5 timelines suggest that not all countries are on-track to meet their individual commitments by 2020. These countries may therefore need to implement emissions reduction measures beyond those currently in place. 

In 2012, 29 countries reported levels above the Gothenburg Protocol's 2020 NOX ceiling, 14 above the NH3 ceiling, 21 above the NMVOCc ceiling, 15 above the SO2 ceiling and 23 above the PM2.5 ceiling.

Share of EEA-33 emissions of main air pollutants by sector group

Data sources:
Data sources:

European legal instruments address directly and indirectly the mitigation of air pollutant emissions from specific source sectors (for details see Indicator Specification).

The newer Member States of the European Union have, in a number of cases, also undergone major economic structural changes since the early 1990s. This has led to a general decline in some activities that made significant contributions to national air pollutant emissions (e.g. heavy industry) and the closure of older, less efficient, power plants. There has also been a modernisation of the road vehicle fleet, introducing more vehicles with improved emissions control.


Sulphur oxides (SOx)

Emissions of SOx are dominated by emissions from the 'Energy production and distribution' sector, which typically accounts for nearly 60% of the total emissions from the EEA-33. This source has also been responsible for the largest emissions reductions since 1990.

Stationary Combustion: Substantial SOx emissions reductions have been made across a number of sectors. The three largest sectors ('Energy production and distribution', 'Energy use in industry' and 'Commercial, institutional and households') have all reduced by 60% or more. However, despite large reductions, the 'Energy production and distribution' sector (encompassing activities such as power and heat generation) still remains the most significant source of SOx in the EEA-33 region, contributing over half of the current total of SOx emissions.

Shipping: Across Europe there is also an increasing awareness of the contribution made to SOx emissions by national and international ship traffic, and especially, whilst at berth, the contribution to air pollution in nearby urban areas (a more detailed discussion of this issue is contained in the TERM indicator fact sheet TERM03 - Transport emissions of air pollutants).

A combination of measures has led to the reductions in SOx emissions:

  • Fuel switching: There have been substantial changes from high-sulphur solid (e.g. coal) and liquid (e.g. heavy fuel oil) fuels to low sulphur fuels (such as natural gas) for power and heat production purposes within the energy, industry and domestic sectors.
  • Abatement equipment: Where high-sulphur fuels are used, flue gas desulphurisation equipment is now installed in new industrial facilities, and has also been retro-fitted to existing facilities.
  • Improvements in energy efficiency: Improvements in energy efficiency have brought about decreases in the demand for energy, which has reduced associated emissions.
  • Sulphur content of fuel: The implementation of several directives within the EU limiting the sulphur content of transport fuel has also contributed to the decrease.

Nitrogen oxides (NOx)

Emissions from 'Road Transport' and 'Non-road Transport' combine to account for almost half of the current NOx emissions in the EEA-33.

Road Transport: Since 1990, a considerable reduction in NOx and other ozone precursor pollutants has occurred in the road transport sector, despite the general increase in transport activity within this sector over the period. This sector alone has contributed to over 40% of the total NOx reduction. The emissions reductions have primarily been achieved as a result of fitting three way catalytic converters for petrol-fuelled cars (driven by the legislative Euro standards11).

Although the largest emissions reductions since 1990, in absolute terms, have occurred in the road transport sector, ambient urban concentrations of NO2 in EU-28 countries in recent years have not fallen by as much as reported emissions. Disparities between trends in NOx emissions and ambient NO2 concentrations (see CSI004) is due in part to the increased penetration of diesel vehicles, and the ‘real-world’ emissions performance of modern diesel vehicles not showing the improvements that were initially suggested by the test cycle emissions factors used in emission inventories – although this is now being addressed in national emissions inventories. It is also due to the increased proportion of NOx emitted directly as NO2 from the exhausts of more modern diesel vehicles, which use catalyst systems for controlling emissions, particularly of particulate matter.

Energy Production and Energy Use in Industry: Emissions of NOx have also declined in the 'Energy production and distribution' sector, and current emissions are approximately half of those in 1990. Furthermore, there have been substantial reductions in the emissions from ‘Energy use in industry’.

These reductions have been achieved through the implementation of measures such as combustion modification (for example the use of low NOx burners), the introduction of flue-gas abatement techniques and fuel-switching from coal to gas. One of the most common forms of combustion modification is to use low NOx burners, which typically can reduce NOx emissions by up to 40%. Flue gas treatment techniques (such as NOx scrubbers, selective catalytic or non-catalytic reduction techniques, i.e. SCR and SNCR) can also be used to remove NOx from the flue gases. Emissions of NOx are higher from coal-fired power plants than from gas-fired plants as the coal contains significant amounts of nitrogen (unlike gas).

Shipping: There is an increasing focus on the increasing relative contribution made to NOx pollutant emissions by national and international ship traffic (a more detailed discussion of this issue is contained in the TERM indicator fact sheet TERM03 - Transport emissions of air pollutants).

Non-methane volatile organic compounds (NMVOC)

Solvent and Product Use: The largest source of current NMVOC emissions is 'Solvent and product use' (approximately 40% of the EEA-33 emissions total). Emissions have been reduced to less than two thirds of those in 1990. Important EU regulatory measures - the Solvent Emissions Directive6 and the Paints Directive7 -were introduced and have reduced the solvent content of products and reduced emissions from industries using solvents.

Road Transport and Non-road Transport: Emissions from 'Road Transport' and 'Non-road Transport' combine to contribute approximately 15% of the total NMVOC emissions. Emissions from the ‘Commercial, Institutional and Households’ sectors make a similar contribution to the total.

Since 1990, a considerable part of the reduction of ozone precursor pollutant emissions (here NMVOC and NOx) has occurred in the road transport sector, despite the general increase in transport activity within this sector over the period. Road transport alone has contributed half of the total NMVOC reduction since 1990. These emissions reductions have primarily been achieved as a result of fitting three way catalytic converters for petrol-fuelled cars (driven by the legislative Euro standards11).

Ammonia (NH3)

Agriculture: Agriculture dominates emissions of NH3, they amount to 95% of total emissions in the EEA-33 region. Emissions primarily arise from the decomposition of urea in animal wastes and uric acid in poultry wastes. Emissions depend on the animal species, age, weight, diet, housing systems, waste management and liquid manure storage techniques.                                                            

Emissions of NH3 have reduced by approximately 30% since 1990, due to changes in the agriculture sector. These have included a reduction in livestock numbers (especially cattle), and changes in the handling and management of both organic manure and synthetic fertilisers.

Fine particulate matter (PM2.5)

Commercial, Institutional and Households: Emissions from the ‘Commercial, Institutional and Households’ sectors contribute over half of the current primary PM2.5 emissions for the EEA-33. Within this sector, emissions are almost exclusively from households (over 95%). Emissions from Turkey show an order of magnitude increase from 2011 to 2012. Excepting this change, current emissions are lower than those in 1990 (by nearly 10%). However the last several years have shown a general trend of increasing emissions from 2007 onwards, and emissions of PM2.5 from wood burning are high compared to most other fuels.

Energy Production and Energy Use in Industry: These sources only account for a combined contribution current EEA-33 emissions of approximately 15%, but have been responsible for the largest absolute decreases in emissions since 1990. They account for half of the emissions reductions since 1990. This reflects several changes in the electricity generating and heavy industrial sectors. Fuel switching away from coal has reduced emissions of PM2.5, and the introduction of abatement equipment such as electrostatic precipitators also acts to significantly reduce the emissions of PM2.5.

Road Transport: Emissions from road transport contribute approximately 15% of the PM2.5 total emission in the EEA-33, but account for nearly a quarter of the reduction in total EEA-33 emissions since 1990. This is a reflection of the improved emissions control technologies that have been introduced, particularly for diesel vehicles.



Supporting information

Indicator definition

This indicator tracks trends since 1990 in anthropogenic emissions of the main air pollutants — NOx, NH3, SOx and NMVOCs. The indicator further tracks trends since 2000 in anthropogenic emissions of PM with a diameter of up to 2.5 μm (i.e. PM2.5) emitted directly into the air (primary PM). All named pollutants have direct or indirect negative effects on human health, vegetation or ecosystems.

The indicator also provides information on emissions by sector, addressing the following source aggregations:

  • 'Energy production and distribution'
  • 'Energy use in industry'
  • 'Industrial processes'
  • 'Road transport'
  • 'Non-road transport'
  • 'Commercial, institutional and households'
  • 'Solvent and product use'
  • 'Agriculture'
  • 'Waste'
  • 'Other'.

Geographically, the indicator covers the EU-28 and EEA-33 countries. The EEA-33 countries include the EU-28 countries (Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden and the United Kingdom) plus European Free Trade Association (EFTA) countries (Iceland, Liechtenstein, Norway and Switzerland) and Turkey.


The total emissions per country are given in gigagrams (Gg; i.e. 1 000 tonnes). The aggregated sector contributions for the emissions of each main pollutant are given in percentages (%).


Policy context and targets

Context description

Current EU air pollution policy is underpinned by the objectives and long-term goals of e.g. the Sixth Environment Action Programme (6EAP; EC, 2002) (covering the 2002–2012 period) to further reduce air pollution and its impacts on ecosystems and biodiversity by 2020, i.e. to attain 'levels of air quality that do not give rise to significant negative impacts on, and risks to, human health and the environment'. This goal has been reinforced in the Seventh Environment Action Programme (7th EAP), which will run until 2020 (EU, 2013). To move towards achieving the TSAP objectives, EU air pollution legislation has followed a twin-track approach of implementing both emission mitigation controls and air‑quality standards. A new strategy, the Clean Air Programme for Europe, was proposed by the European Commission at the end of 2013 (EU, 2013).

Internationally, the 1979 UNECE LRTAP Convention (UNECE, 1979) was a first step towards addressing the impacts of air pollution on health and the environment. A centrepiece of the convention is the 1999 ‘Gothenburg Protocol to Abate Acidification, Eutrophication and Ground-level Ozone’, subsequently amended in 2012 (UNECE, 2012). The amended protocol sets emission ceilings (limits) for the year 2010 and national emission reduction commitments for the emission of the main air pollutants, namely SOx, NOx, NH3 and NMVOCs. It also includes reduction commitments for PM2.5 emissions for 2020. Under the protocol, the critical loads concept was established as a tool for informing political discussions related to damage to sensitive ecosystems (see CSI 005). Critical ozone levels (concentrations) for vegetation were also defined under the LRTAP Convention.

The 1999 Gothenburg Protocol was followed in 2001 by the EU's NECD which has since been repealed by a revised NEC Directive in 2016 (EU, 2016). The original directive introduced legally binding national emission limits for four main air pollutants: SO2, NOx, NH3 and NMVOCs. The directive requires EU Member States to have met emission ceilings by 2010 and in the years thereafter, with emission reduction commitments established for 2020 and 2030 for the four main pollutants and PM2.5.  The goal is to comply with the amended Gothenburg Protocol by 2020, followed by more ambitious reductions from 2030 onwards. The human health and environmental objectives defined in the NECD, the Gothenburg Protocol and the EU’s Air Quality Directive (EU, 2008a) are addressed by indicators CSI004 and CSI005.

Regulation addressing ambient air concentrations

The European directives currently regulating the ambient air concentrations of the main pollutants are designed to avoid, prevent or reduce the harmful effects of air pollutants on human health and the environment by implementing limit or target values for ambient concentrations of air pollutants. They are:

  • Directive 2008/50/EC on ambient air quality and cleaner air for Europe, which regulates ambient air concentrations of SO2, NO2 and other nitrogen oxides, PM10 and PM2.5, lead, benzene (C6H6), carbon monoxide (CO) and ozone (EU, 2008a);
  • Directive 2004/107/EC relating to arsenic, cadmium, mercury, nickel and polycyclic aromatic hydrocarbons in ambient air (EU, 2004).

In the case of non-compliance with the air quality limit and target values stipulated in European legislation, air quality management plans must be developed and implemented in the areas in which exceedances occur. These plans should aim to bring concentrations of air pollutants to levels below the limit and target values. To ensure overall coherence, and consistency between different policies, air quality plans should be consistent (if feasible) and integrated with plans and programmes in line with the directives regulating air pollutant emissions.

Legal instruments at European level that address emissions directly or indirectly

Source-specific EU legislation focuses on industrial emissions, road and off-road vehicle emissions, fuel quality standards, etc., by setting emission standards, requiring the use of best-available technology or setting requirements on fuel composition. In addition, several legal instruments are used to reduce environmental impacts from different activities or to promote environmentally friendly behaviour, and these also contribute indirectly to reducing air pollution, as summarised below.

End-of-pipe control in industrial installations:

  • Directive 2001/80/EC on the limitation of emissions of certain pollutants into the air from large combustion plants (the LCP Directive; EC, 2001); the overall aim of the LCP Directive is to reduce emissions of acidifying pollutants, PM and ozone precursors, and the directive addresses emissions from large combustion plants — i.e. those whose rated thermal input is equal to or greater than 50 MW;
  • Directive 2010/75/EU on industrial emissions (integrated pollution prevention and control) (EU, 2010), which targets certain industrial, agricultural and waste treatment installations.


Emission standards for cars:

  • The Euro Regulations set standards for road vehicle emissions. The Euro 5 and 6 standards are defined in Regulations (EC) No 692/2008 (EU, 2008b) and No 595/2009 (EU, 2009a). The Communication CARS 2020 (EC, 2012) sets out a timetable for implementation of the Euro 6 vehicle standards in real-world driving conditions, and for the revision of the non-road mobile machinery legislation.


Handling and storage:

  • Directive 94/63/EC on the control of volatile organic compound (VOC) emissions resulting from the storage of petrol and its distribution from terminals to service stations (EU, 1994) and Directive 2009/126/EC on Stage II petrol vapour recovery during refuelling of motor vehicles at service stations (EU, 2009b);
  • Directive 1999/13/EC on the limitation of emissions of VOCs due to the use of organic solvents in certain activities and installations (EU, 1999a).


Fuel quality:

  • Directive 2012/33/EU (EU, 2012) amending Directive 1999/32/EC as regards the sulphur content of marine fuels, Directive 1999/32/EC on the reduction of the sulphur content of certain liquid fuels (EU, 1999b) and Directive 2003/17/EC (amending Directive 98/70/EC) relating to the quality of petrol and diesel fuels (EU, 2003a).


International shipping:

  • The Marine Pollution Convention, MARPOL73/78 (IMO, 1973), is the main international convention on preventing ships from polluting as a result of operational or accidental causes. Annex VI sets limits on emissions of SOx, NOx, VOCs and PM in ship exhausts, and prohibits deliberate emissions of ozone-depleting substances.
  • For international shipping, tighter shipping fuel standards and emission standards at IMO/MARPOL level resulted in the recent revision of the Sulphur Content of Fuel Directive (adopted as 2012/33/EU; EU, 2012).


In addition to the policy instruments outlined above, there are several EU directives that also contribute indirectly to efforts to minimise air pollution. These directives are intended to reduce environmental impacts, including on climate change, and/or to promote environmentally friendly behaviour. Some examples are outlined below.


  • The Nitrates Directive, i.e. Directive 91/676/EEC concerning the protection of waters against pollution caused by nitrates from agricultural sources (EU, 1991), particularly through the implementation of agricultural practices that limit fertiliser application and prevent nitrate losses, helps to reduce agricultural emissions of nitrogen compounds to air.

Energy taxation:

  • The Energy Taxation Directive, i.e. Directive 2003/96/EC restructuring the Community framework for the taxation of energy products and electricity (EU, 2003b), establishes minimum taxes for motor fuels, heating fuels and electricity, depending on the energy content of the product and the amount of CO2 it emits. This directive aims to promote energy efficiency and less‑polluting energy products.



  • The Ecodesign Directive, i.e. Directive 2009/125/EC establishing a framework for the setting of ecodesign requirements for energy-related products, provides consistent EU-wide rules for improving the environmental performance of energy-related products through ecodesign (EU, 2009). This should benefit both businesses and consumers by enhancing product quality, achieving energy savings and thereby increasing environmental protection. Energy-related products (the use of which impacts energy consumption) include products that use, generate, transfer or measure energy (electricity, gas and fossil fuel). This includes boilers, computers, televisions, transformers, industrial fans and industrial furnaces. Some energy-related products do not use energy, but do have an impact on energy, and can therefore contribute to related savings, such as windows, insulation material, shower heads and taps.
  • The Ecodesign Directive is complemented and supported by the Energy Labelling Directive (EU, 2010b) and Directive 2006/32/EC on energy end-use efficiency and energy (EU, 2006).



National Emission Ceilings Directive (2001/81/EC)

The NECD (EU, 2001) sets pollutant-specific and legally binding emission ceilings for NOx, NMVOCs, SOx and NH3 for each EU Member State. The directive requires Member States to have met the ceilings and interim environmental objectives by 2010 and in the years thereafter (EEA, 2019). The directive sets specific environmental objectives that address the impacts of acidification and eutrophication on ecosystems, and the harmful effects of ozone on vegetation and human health (see CSI 005).

The NECD was reviewed as part of the Clean Air Policy Package. In December 2016, the Council adopted the new directive and reporting under this directive already started in February 2017. The new directive repeals and replaces the current EU regime on the annual capping of national emissions of air pollutants, as defined in Directive 2001/81/EC. By doing so, it ensures that the national emission ceilings (NECs) set in the current NECD (2001/81/EC) for 2010 onwards for SOx, NOx, NMVOCs and NH3 shall apply until 2020, and it establishes new national emission 'reduction commitments', which are applicable from 2020 and from 2030, for SOx, NOx, NMVOCs, NH3 and PM2.5. The reduction commitments are binding for the period from 2020 to 2029 and from 2030 onwards. In principle, the commitments are indicative for 2025 by a linear emission reduction trajectory. A non-linear reduction trajectory is permissible if it is economically and technically more efficient, and provided that, from 2025, it progressively converges with the linear reduction trajectory.


UNECE Convention on Long-range Transboundary Air Pollution Gothenburg Protocol (1999; amended in 2012)

The amended Gothenburg Protocol sets national ceilings (limits) for the emission of the main air pollutants, namely SOx, NOx, NH3, NMVOCs and primary PM2.5 (UNECE, 2012). The EU as a whole has ratified the protocol, and reports EU emissions to the UNECE (EEA, 2016b).

The target under the amended protocol (UNECE, 2012) is to ensure that — in the long term and using a stepwise approach that takes into account advances in scientific knowledge — atmospheric depositions or concentrations do not exceed critical loads for the nutrient nitrogen (see CSI 005). Critical levels for the protection of crops (AOT40c) and for the protection of forests (AOT40f) have also been defined under the LRTAP Convention, and the critical level for crops is consistent with the EU long-term objective for vegetation (see CSI 005).

The 2010 targets under the NECD and Gothenburg Protocol are included in the EEA’s NEC data viewer and the LRTAP data viewer.

Related policy documents

  • 7th Environment Action Programme
    DECISION No 1386/2013/EU OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 20 November 2013 on a General Union Environment Action Programme to 2020 ‘Living well, within the limits of our planet’. In November 2013, the European Parliament and the European Council adopted the 7 th EU Environment Action Programme to 2020 ‘Living well, within the limits of our planet’. This programme is intended to help guide EU action on the environment and climate change up to and beyond 2020 based on the following vision: ‘In 2050, we live well, within the planet’s ecological limits. Our prosperity and healthy environment stem from an innovative, circular economy where nothing is wasted and where natural resources are managed sustainably, and biodiversity is protected, valued and restored in ways that enhance our society’s resilience. Our low-carbon growth has long been decoupled from resource use, setting the pace for a safe and sustainable global society.’
  • 1999 Protocol to Abate Acidification, Eutrophication and Ground-level Ozone
    Convention on Long-range Transboundary Air Pollution 1999 Protocol to Abate Acidification, Eutrophication and Ground-level Ozone, amended on 4 May 2012.
  • A Clean Air Programme for Europe
    Communication from the Commission to the Council, the European Parliament, the European Economic and Social Committee and the Committee of the Regions - "A Clean Air Programme for Europe", COM(2013) 918 final
  • Directive 2008/50/EC, air quality
    Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe.
  • Sixth Environment Action Programme (decision No 1600/2002/EC)
    DECISION No 1600/2002/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 22 July 2002 laying down the Sixth Community Environment Action Programme
  • UNECE Convention on Long-range Transboundary Air Pollution
    UNECE Convention on Long-range Transboundary Air Pollution.


Methodology for indicator calculation

This indicator is based on national total and sectoral emissions officially reported to the EEA and the UNECE 'Co-operative programme for monitoring and evaluation of the long-range transmissions of air pollutants in Europe' (EMEP) LRTAP Convention. For the EU-28 Member States, the data used are consistent with the emission data reported by the EU in its annual submission to the LRTAP Convention.

Recommended methodologies for emission inventory estimation are compiled in the EMEP/EEA Air Pollutant Emission Inventory Guidebook (EMEP/EEA, 2016). Base data are available from the EEA Data Service and the EMEP website (Centre on Emission Inventories and Projections (CEIP)). Where necessary, gaps in reported data are filled by the European Topic Centre on Air and Climate Change using simple interpolation techniques (see below). The final gap-filled data used in this indicator are available from the EEA’s LRTAP data viewer.


Base data, reported in the UNECE/EMEP nomenclature for reporting (NFR) sector format, are aggregated into the following EEA sector codes to obtain a consistent reporting format across all countries and pollutants:

  • Energy production and distribution: emissions from public heat and electricity generation, oil refining, production of solid fuels, extraction and distribution of solid fossil fuels and geothermal energy;
  • Energy use in industry: emissions from combustion processes used in the manufacturing industry including boilers, gas turbines and stationary engines;
  • Industrial processes and product use: emissions derived from non-combustion related processes such as the production of minerals, chemicals and metal production, non-combustion-related emissions mainly in the services and household sectors including from activities such as paint application, dry-cleaning and other uses of solvents;
  • Road transport: light and heavy duty vehicles, passenger cars and motorcycles;
  • Non-road transport: railways, domestic shipping, certain aircraft movements and non-road mobile machinery used in agriculture and forestry;
  • Commercial, institutional and households: emissions principally occurring from fuel combustion in the services and household sectors;
  • Agriculture: manure management, fertiliser application, field-burning of agricultural wastes;
  • Waste: incineration, wastewater management;
  • Other: emissions included in national totals for the entire territory that are not allocated to any other sector.


The following table shows the conversion of nomenclature for reporting (NFR14) sector codes used for reporting by countries into EEA sector codes:

EEA classification

Non-greenhouse gases (GHGs; NFR14)


National totals

National total


Energy production and distribution

1A1, 1A3e, 1B


Energy use in industry



Road transport



Non-road transport (non-road mobile machinery)

1A3 (exl 1A3b)


Industrial processes and product use











Commercial, institutional and households

1A4ai, 1A4aii, 1A4bi, 1A4bii, 1A4ci, 1A4cii, 1A5a, 1A5b



Methodology for gap filling

An improved gap-filling methodology was implemented in 2010 that enables a complete time-series trend for the main air pollutants (e.g. NOx, SOx, NMVOCs, NH3 and CO) to be compiled. In cases in which countries did not report emissions for any year, gap-filling could not be applied. For these pollutants, therefore, the aggregated data are not yet complete and are likely to underestimate true emissions. Further methodological details of the gap-filling procedure are provided in section 'Data gaps and gap-filling' of the European Union emission inventory report 1990–2017 under the UNECE Convention on Long-range Transboundary Air Pollution (LRTAP) (EEA, 2019).

Methodology references

  • EEA, 2019 European Union emission inventory report 1990 — 201 under the UNECE Convention on Long-range Transboundary Air Pollution (LRTAP). EEA technical report No 9/2019. Copenhagen.
  • • EMEP/EEA, 2016 EMEP/EEA Air Pollutant Emission Inventory Guidebook.
  • EMEP, 2010 Transboundary, acidification, eutrophication and ground level ozone in Europe in 2008 Estimated dispersion of acidifying and eutrophying compounds and comparison with observations.


Methodology uncertainty

The use of a gap-filling methodology for countries that have not reported emissions for one or more years can potentially lead to artificial trends, but it is considered unavoidable if a comprehensive and comparable set of emission data for European countries is required for policy analysis purposes.


Data sets uncertainty

NOx emission estimates in Europe are thought to have an uncertainty of about ±20 % (EMEP (2010), as the NOx emitted is from both the fuel burnt and the combustion of air and so cannot be estimated accurately from fuel nitrogen alone. However, because of the need for interpolation to account for missing data, the complete data set used will have a higher degree of uncertainty. The overall trend is likely to be more accurate than individual absolute annual values — the annual values are not independent of each other.

Overall scoring (1–3; 1 = no major problems, 3 = major reservations):

  • relevancy: 1
  • accuracy: 2
  • comparability over time: 2
  • comparability over space: 2.

SOx emission estimates in Europe are thought to have an uncertainty of about ±10 %, as the sulphur comes from only the fuel burnt and therefore can be more accurately estimated than emissions of NOx. However, because of the need for interpolation to account for missing data, the complete data set used will have a higher degree of uncertainty. EMEP has compared modelled and measured concentrations throughout Europe (EMEP, 2010). From these studies, differences in the annual averages have been estimated to be ±30 %, which is consistent with an inventory uncertainty of ±10 % (there are also uncertainties in the measurements and especially the modelling). The trend is likely to be much more accurate than individual absolute values.

Overall scoring (1–3; 1 = no major problems, 3 = major reservations):

  • relevancy: 1
  • accuracy: 2
  • comparability over time: 2
  • comparability over space: 2.

NH3 emission estimates in Europe are more uncertain than those for NOx, SOx and NMVOCs, largely because of the diverse nature of major agricultural sources. It is estimated that they have an uncertainty of around ±30 % (EMEP, 2009). The overall trend is likely to be more accurate than the individual absolute annual values — the annual values are not independent of each other. 

Overall scoring (1–3; 1 = no major problems, 3 = major reservations):

  • relevancy: 1
  • accuracy: 2
  • comparability over time: 2
  • comparability over space: 2.

Rationale uncertainty

This indicator is regularly updated by the EEA and is used in state of the environment assessments. The uncertainties related to methodology and data sets are therefore important.

Data sources

Other info

DPSIR: Pressure
Typology: Policy-effectiveness indicator (Type D)
Indicator codes
  • CSI 040
  • AIR 005
Frequency of updates
Updates are scheduled once per year
EEA Contact Info


Geographic coverage

Temporal coverage