Sulphur dioxide (SO2) emissions

Assessment versions

Published (reviewed and quality assured)

• No published assessments

Rationale

Justification for indicator selection

Sulphur dioxide (SO₂) is emitted when fuels containing sulphur are combusted. Sulphur dioxide is a pollutant that contributes to acid deposition, which, in turn, can lead to potential changes in soil and water quality. The subsequent impacts of acid deposition can be significant, including adverse effects on aquatic ecosystems in rivers and lakes and damage to forests, crops and other vegetation. In many cases, the deposition of acidifying substances still exceeds the critical loads of the ecosystems (see EEA indicator CSI 005 'Exposure of ecosystems to acidification, eutrophication and ozone'). Acidification can also damage buildings and cultural monuments. Further details concerning emissions of acidifying pollutants are provided in EEA's Core Set Indicator CSI 001 'Emissions of acidifying substances'.

As a secondary particulate matter precursor, SO₂ also contributes to the formation of particulate aerosols in the atmosphere. Particulate matter is an important air pollutant due to its adverse impacts on human health, and SO₂ is therefore also indirectly linked to effects on human health (see EEA's Core Set Indicator CSI 003 'Emissions of primary particles and secondary particulate precursors' for further details concerning emissions of particulate matter).

Scientific references

• No rationale references available

Indicator definition

• The indicator tracks trends since 1990 in anthropogenic emissions of sulphur dioxide.
• The indicator also provides information on emissions by sector: 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.
• Geographical coverage: EEA-32. The EEA-32 country grouping includes countries of the EU-27 (Austria, Belgium, Bulgaria, Cyprus, 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) EFTA-4 (Iceland, Liechtenstein, Switzerland and Norway) and Turkey.
• Temporal coverage: 1990-2010

Units

ktonnes (1000 tonnes)

Policy context and targets

Context description

A number of policies have been implemented within Europe that either directly or indirectly act to reduce emissions of SO₂. These include:

• The National Emission Ceilings Directive 2001/81/EC (NECD), which entered into force in the European Community in 2001: The NECD sets emission ceilings for four important air pollutants (SO₂, nitrogen oxides (NO_x)_, ammonia (NH₃) and non-methane volatile organic compounds (NMVOCs)) to be achieved from 2010 onwards for each Member State. The ceilings are designed to improve the protection of the environment and human health in the Community against risks of adverse effects arising from acidification, eutrophication and ground level ozone. The NECD is presently under review, the European Commission may adopt a proposal for a revised Directive during 2010.

• The Gothenburg Protocol (1999) to the United Nations Economic Commission for Europe's (UNECE) Convention on Long-Range Transboundary Air Pollution (LRTAP Convention) to abate acidification, eutrophication and ground-level ozone: A key objective of the protocol is to regulate emissions on a regional basis within Europe and to protect eco-systems from transboundary pollution by setting emission reduction ceilings to be reached by 2010 for the same four pollutants as addressed in the NECD (i.e. SO₂, NO_x, NH₃ and NMVOCs). Overall, for EU Member States, the ceilings set within the Gothenburg protocol are generally either slightly less strict or the same as the emission ceilings specified in the NECD.
• The Directive for the Sulphur content of Certain Fuels (93/12/EC): This requires Member States to cease the use of heavy fuel oil with a sulphur content greater than 1% by mass from 2001, and the use of gas oil with a sulphur content greater than 0.2% from 2001 and greater than 0.1% from 2008.
• The Large Combustion Plant Directive 2001/80/EC (LCPD): This is important in reducing emissions of SO₂, NO_x and dust from combustion plants with a thermal input capacity equal to or greater than 50 MW. Installations within the scope of this Directive include power stations, petroleum refineries, steelworks and other industrial processes running on solid, liquid and gaseous fuels. "New" plants must meet the emission limit values (ELVs) given in the LCPD. However Member States can choose to meet obligations for existing plants (i.e. those in operation pre-1987) by either complying with the ELVs or by operating within a national emission reduction plan (NERP) that sets a ceiling for each pollutant. The interaction of the LCPD and the IPPC Directive (see below) is currently being examined as part of a review of the IPPC Directive. 
• The Directive on Integrated Pollution Prevention and Control (96/61/EC), which entered into force in 1999: This Directive aims to prevent or minimise pollution to air, water or land from various industrial sources throughout the European Union. Those installations covered by Annex I of the IPPC Directive are required to obtain authorisation from the authorities to operate. New installations and existing installations, which are subject to 'substantial changes', have been obliged to meet the requirements of the IPPC Directive since 30 October 1999. Other existing installations must have been brought into compliance by the 30 October 2007. The emission limit values outlined in the permit conditions must be based on best available techniques (BAT). The Commission has been undertaking a review of the IPPC Directive and related legislation on industrial emissions and, on 21 December 2007, adopted a proposal for a Directive on industrial emissions. The proposal recasts seven existing Directives relating to industrial emissions (including IPPC and the LCPD) into a single legislative instrument.
• The aim of the Directive 96/62/EC on ambient air quality assessment and management (the 'Air Quality Framework Directive') is to maintain and improve air quality within the European Community by establishing objectives for ambient air, drawing up common methods and criteria for assessing air quality and obtaining and disseminating information. The "Daughter" Directive 99/30/EC of the Air Quality Framework Directive entered into force in 1999 and sets limit values for concentrations of several pollutants including sulphur dioxide.
• The European Sulphur Content of Marine Fuels Directive (SCMFD) (2005/33/EC): This requires "Member States to ensure that marine gas oils are not placed on the market in their territory if the sulphur content exceeds 0.1% by mass", amongst other requirements.
• The Marpol Convention: This convention covers the prevention of pollution of the marine environment by ships from operational or accidental causes. It is a combination of two treaties adopted in 1973 and 1978 and updated by amendments over the years since. Annex VI covers the prevention of air pollution from ships and sets limits on sulphur dioxide emissions from ship exhausts. This came into force in May 2005.
• Fuel quality Directive 98/70/EC and sulphur-free fuels Directive 2003/17/EC: Current market grade petrol and diesel fuels do not have a sulphur level exceeding 50 parts per million (ppm). This is the maximum level of sulphur permitted for road fuels in EU Member States from 2005 under the fuel quality Directive 98/70/EC. The introduction of "sulphur-free fuels", with sulphur levels less than 10 ppm, is required by 1 January 2009 under Directive 2003/17/EC.

Targets

Emissions of SO₂ are covered by the EU National Emission Ceilings Directive (NECD) (2001/81/EC) and the Gothenburg protocol under the United Nations Convention on Long-Range Transboundary Air Pollution (LRTAP Convention) (UNECE 1999). The NECD generally involves slightly stricter emission reduction targets than the Gothenburg Protocol for EU-15 Member States for the period 1990-2010. The Gothenburg Protocol entered into force on 17 May 2005, after ratification by 16 countries early in 2005. The 2012 revision to the Gothenburg protocol proposed emission reduction targets for 2020 relative to 2005 reported emissions for all EU-27 Member States and some EEA-32 non-EU member states.

Table: 2010 SO₂ ceilings under the NEC Directive and the Gothenburg Protocol (kt)

^* Iceland and Turkey do not have a ceiling under either the NEC Directive or the Gothenburg protocol.

Related policy documents

• Council Directive 96/61/EC (IPPC)
  Council Directive 96/61/EC of 24 September 1996 concerning Integrated Pollution Prevention and Control (IPPC). Official Journal L 257.
• Council Directive 96/62/EC of 27 September 1996
  Council Directive 96/62/EC of 27 September 1996 on ambient air quality assessment and management.
• Directive 98/70/EC, quality of petrol and diesel fuels
  Directive 98/70/EC of the European Parliament and of the Council of 13 October 1998 relating to the quality of petrol and diesel fuels and amending Directive 93/12/EEC
• Directive 2001/80/EC, large combustion plants
  Directive 2001/80/EC of the European Parliament and of the Council of 23 October 2001 on the limitation of emissions of certain pollutants into the air from large combustion plants
• Directive 2001/81/EC, national emission ceilings
  Directive 2001/81/EC, on nation al emissions ceilings (NECD) for certain atmospheric pollutants. Emission reduction targets for the new EU10 Member States have been specified in the Treaty of Accession to the European Union 2003  [The Treaty of Accession 2003 of the Czech Republic, Estonia, Cyprus, Latvia, Lithuania, Hungary, Malta, Poland, Slovenia and Slovakia. AA2003/ACT/Annex II/en 2072] in order that they can comply with the NECD.
• Sulphur content of Certain Fuels (93/12/EC)
  Requires Member States to cease the use of heavy fuel oil with a sulphur content greater than 1% by mass from 2001, and the use of gas oil with a sulphur content greater than 0.2% from 2001 and greater than 0.1% from 2008
• UNECE Convention on Long-range Transboundary Air Pollution
  UNECE Convention on Long-range Transboundary Air Pollution.

Methodology

Methodology for indicator calculation

This indicator is based on officially reported national total and sectoral emissions to the EEA and 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 2011. For the EU-27 Member States, the data used is consistent with the emissions 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, 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/). Where necessary, gaps in reported data are filled by European Topic Centre/EEA using simple interpolation techniques (see below). The final gap-filled data used in this indicator is available from the EEA Data Service (http://dataservice.eea.europa.eu/PivotApp/pivot.aspx?pivotid=478)

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: emissions derived from non-combustion related processes such as the production of minerals, chemicals and metal production;
• 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;
• Solvent and product use: non-combustion related emissions mainly in the services and households sectors including activities such as paint application, dry-cleaning and other use of solvents;
• Agriculture: manure management, fertiliser application, field-burning of agricultural wastes
• Waste: incineration, waste-water management;
• Other: emissions included in national total for entire territory not allocated to any other sector.

The following table shows the conversion of Nomenclature for Reporting (NFR) sector codes used for reporting by countries into EEA sector codes:

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 (eg NO_X, SO_X, NMVOC, NH₃ and CO) to be compiled. In cases where countries did not report emissions for any year, it meant that gap-filling could not be applied. For these pollutants, therefore, the aggregated data is not yet complete and is likely to underestimate true emissions. Further methodological details of the gap-filling procedure are provided in section 1.4.2 'Data gaps and gap-filling' of the European Union emission inventory report 1990–2009 under the UNECE Convention on Long-range Transboundary Air Pollution (LRTAP).

Methodology references

• EEA (2011). European Union emission inventory report 1990 — 2009 under the UNECE Convention on Long-range Transboundary Air Pollution (LRTAP). EEA technical report No 9/2011. Copenhagen.
• EMEP/EEA (2009). EMEP/EEA Air Pollutant Emission Inventory Guidebook - 2009 This 2009 update of the emission inventory guidebook prepared by the UNECE/EMEP Task Force on Emissions Inventories and Projections provides a comprehensive guide to state-of-the-art atmospheric emissions inventory methodology. Its intention is to support reporting under the UNECE Convention on Long-range Transboundary Air Pollution and the EU National Emission Ceilings Directive.
• EMEP (2010). Transboundary, acidification, eutrophication and ground level ozone in Europe in 2008 Estimated dispersion of acidifying and eutrophying compounds and comparison with observations.

Data specifications

EEA data references

• National Emission Ceilings (NEC) Directive Inventory provided by Directorate-General for Environment (DG ENV)
• National emissions reported to the Convention on Long-range Transboundary Air Pollution (LRTAP Convention) provided by United Nations Economic Commission for Europe (UNECE)

Data sources in latest figures

Uncertainties

Methodology uncertainty

The use of gap-filling when countries 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 emissions data for European countries is required for policy analysis purposes.

Data sets uncertainty

SO₂ emission estimates in Europe are thought to have an uncertainty of about ±10% as the sulphur 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 will have higher 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

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 of importance. Any uncertainties involved in the calculation and in the data sets need to be accurately communicated in the assessment, to prevent erroneous messages influencing policy actions or processes.