AP1 EEA-32 Sulphur dioxide SO 2 emissions

Transcription

1 AP1 EEA-32 Sulphur dioxide SO 2 emissions Key messages EEA-32 emissions of sulphur dioxide (SO 2 ) have decreased by 66% between 1990 and In 2005, the most significant source of SO 2 emissions was the energy industries sector (41%), followed by emissions occurring from industrial processes (35%) and industrial energy use (13%). The reduction in emissions since 1990 has been achieved as a result of a combination of measures, including fuel-switching in energy-related sectors away from high sulphur-containing solid and liquid fuels to low sulphur fuels such as natural gas, the fitting of flue gas desulphurisation abatement technology in industrial facilities and the impact of European Community directives relating to the sulphur content of certain liquid fuels. Thirteen of the EU-27 Member States have already reduced their national SO 2 emissions below the level of the emission ceilings set in the National Emission Ceilings Directive (NECD), while a number of others are close to meeting their ceilings. However, a small number of Member States still need to make significant further reductions in order to meet their respective ceilings under the NECD. Environmental context: Sulphur dioxide is emitted when fuels containing sulphur are combusted. It is a pollutant which contributes to acid deposition which in turn can lead to potential changes occurring 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. SO 2 emission also contributes to formation of particulate matter in the atmosphere, an important air pollutant in terms of its adverse impact on human health. Figure 1 : Emission trends of SO 2 for a) EEA-32; b) EU-15; c) New EU-12; d) EFTA-4 and e) CC-3 Figure 1a) EEA Index kt emission Sulphur dioxide 0 Notes: No data available for Iceland 1

2 Figure 1b) EU Index kt emission NECD Target Sulphur dioxide NECD Target path 2010 NECD Target 0 Figure 1c) New EU Index kt emission 40 NECD Target Sulphur dioxide NECD Target path 2010 NECD Target 2

3 Figure 1d) EFTA Index kt emission Sulphur dioxide 0 Notes: No data available for Iceland Figure 1e) CC Index kt emission Sulphur dioxide 0 Note: The increase in emissions for 1999 is caused by a significant increase in the SO 2 national total reported by Turkey for this year. 3

4 Figure 2: The contribution made by main economic sectors ( 1 ) to SO 2 emissions in 2005 for a) EEA-32; b) EU-15; c) New EU-12; d) EFTA-4 and e) CC-3 (%). Figure 2a) EEA % 6.4% 12.6% 1.8% 2.2% 0.9% 0.1% 41.4% Notes: No data available for Iceland 1 Energy industry : emissions from public heat and electricity generation, oil refining and production of solid fuels; Fugitive emissions : emissions from extraction and distribution of solid fossil fuels and geothermal energy; : emissions from combustion processes used in the manufacturing industry including boilers, gas turbines and stationary engines; Industry (processes) : emissions derived from non-combustion related processes such as the production of minerals, chemicals and metal production; : emissions principally occurring from fuel combustion in the services and household sectors; Other (non-energy): non-combustion related emissions mainly in the services and households sectors including activities such as paint application, dry-cleaning and other use of solvents; Road transport : combustion-related emissions from light and heavy duty vehicles, passenger cars and motorcycles and including tyre and brake-wear abrasion; Off-road transport : railways, domestic shipping, certain aircraft movements, and non-road mobile machinery used in agriculture and forestry; : emissions derived from agriculture-related activities including manure management, fertiliser application and field-burning of agricultural wastes; : incineration, waste-water management. 4

5 Figure 2b) EU % 16.90% 5.45% 61.97% 5.78% 0.00% 4.83% 0.93% 0.12% 0.01% Figure 2c) New EU-12 58% 5% 0% 1% 0% 7% 0% 0% 29% 0% 5

6 Figure 2d) EFTA-4 0.3% 10.8% 3.3% 0.1% 9.5% 4.2% % 36.3% Notes: No data available for Iceland Figure 2e) CC-3 0.2% 0.3% 4.8% 13.8% 1.9% 49.2% 28.0% 1.8% 6

7 Figure 3: Change (%) in SO 2 emissions in each sector , for a) EEA-32 b) EU-15; c) New EU-12; d) EFTA-4 and e) CC-3 country groupings. Figure 3a) EEA-32-63% Unallocated 401% -> -84% -34% 7% -74% 509% -> -68% -51% -65% -86% -90% -70% -50% -30% -10% 10% 30% 50% 70% 90% Notes: No data available for Iceland Figure 3b) EU-15-68% Unallocated <- 524% -92% -42% -8% -82% -40% -73% -59% -71% -88% -100% -80% -60% -40% -20% 0% 7

8 Figure 3c) New EU-12-65% Unallocated 4104% -> -90% 14% 0% -76% 1476% -> -74% 51% -63% -100% -80% -60% -40% -20% 0% 20% 40% 60% 80% 100% Note: The large increase in is due to inconsistencies between the SO 2 national total and data reported by Romania for this sector. Figure 3d) EFTA-4 3% Unallocated -100% -98% -52% 47% -54% -51% -65% -54% -35% 0% -110% -90% -70% -50% -30% -10% 10% 30% 50% Notes: No data available for Iceland 8

9 Figure 3e) CC-3-98% Unallocated -82% 5% -35% 36% -3% -59% -13% 0% -4% 0% -100% -80% -60% -40% -20% 0% 20% 40% Figure 4: The percentage contribution made by each sector with respect to the total change in SO 2 emissions for a) EEA-32; b) EU-15; c) New EU-12; d) EFTA-4 and e) CC-3 country groupings Figure 4a) EEA-32 0% Unallocated -21% -4% -1% 0% -14% 23% -21% -1% -61% 0% -70% -60% -50% -40% -30% -20% -10% 0% 10% 20% 30% 9

10 Notes: No data available for Iceland Figure 4b) EU-15 Unallocated -0.1% -0.1% -4.4% -1.4% -10.4% -1.5% -18.1% -2.4% -61.6% -70% -50% -30% -10% 10% Figure 4c) New EU-12 Unallocated -62.4% -2.5% 0.1% -18.5% 60.6% -22.4% 0.2% -55.1% -70% -50% -30% -10% 10% 30% 50% 70% 10

11 Figure 4d) EFTA-4 Unallocated 0.1% -13.1% -9.0% -18.1% -29.8% -22.4% -3.8% -3.9% -30% -20% -10% 0% 10% Notes: Data for Iceland not included (reported NO/NA for the entire time series) Figure 4e) CC-3 0.1% Unallocated % -0.6% 0.3% -0.2% 1.5% 8.3% 12.0% 5.7% Source: EEA/ETC-AC (2007) -140% -120% -100% -80% -60% -40% -20% 0% 20% 11

12 Environmental Context Sulphur dioxide (SO 2 ) is emitted when fuels containing sulphur are combusted. Sulphur dioxide is a pollutant which contributes to acid deposition which in turn can lead to potential changes occurring 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 precursor, SO 2 also contributes to the formation of particulate aerosols in the atmosphere. Particulate matter is an important air pollutant due to their adverse impacts on human health, and SO 2 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. Policy objectives and measures A number of policies have been implemented within Europe that either directly or indirectly act to reduce emissions of SO 2. These include: The National Emission Ceilings Directive 2001/81/EC (NECD) which entered into force in the European Community in The NECD sets emission ceilings for four important air pollutants (SO 2, nitrogen oxides (NO x ), ammonia (NH 3 ) 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 in the Community of the environment and human health against risks of adverse effects arising from acidification, eutrophication and ground level ozone. The NECD is presently under review, the European Commission anticipates adopting a proposal for a revised Directive mid 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 4 pollutants as addressed in the NECD (i.e. SO 2, NO x, NH 3 and NMVOCs). Overall for the 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) is important in reducing emissions of SO 2, NO x and dust from combustion plants having 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 plant must meet the emission limit values (ELVs) given in the LCPD. However Member States can choose to meet obligations for existing plant (i.e. those in operation per-1987) by either complying with the ELVs or they can operate 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) entered into force in It 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 required to meet 12

13 the requirements of the IPPC Directive since 30 th October Other existing installations must have been brought into compliance by the 30 th October 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 the 21 st 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) 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 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 it sets limits on sulphur dioxide emissions from ship exhausts. This came into force in May Current market grade petrol and diesel fuels do not have a sulphur level exceeding 50 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 <10 ppm, is required by 1 st January 2009 under Directive 2003/17/EC. Assessment - EEA-32 emissions of SO 2 have decreased by 66% between 1990 and Substantial emission reductions have been made across a number of sectors including: road transport (84% reduction between 1990 and 2005), other energy (74%), industry energy (68%) and energy industries (65% between 1990 and 2005). - The energy industries sector (encompassing activities such as power and heat generation) is responsible for the largest reduction (in absolute terms) of emissions, contributing more than 60% of the total reduction in SO 2 emissions reported by countries. Nevertheless, despite this significant reduction, this single sector remains the most significant source of SO 2 in the EEA-32 region. Across Europe there is also an increasing awareness of the contribution made to SO 2 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). - A combination of measures has led to the reductions in SO 2 emissions. This includes fuelswitching 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 industries, industry and domestic sectors, improvements in energy efficiency and the installation of flue gas desulphurisation equipment in new and existing industrial facilities. The implementation of several directives within the EU limiting the sulphur content of fuel quality has also contributed to the decrease. - The newer Member States of the European Union have in a number of cases also undergone significant economic structural changes since the early 1990s which has led to a general decline in certain activities which previously contributed significantly to high levels of sulphur emissions e.g. heavy industry and the closure of older inefficient power plants. - Within the EEA-32 group of countries, all have reported lower emissions in 2005 compared to 1990 except Greece (+9%), Cyprus (+16%) and Turkey (75%). 13

14 Figure 5a: Change in EU-15 national SO 2 emissions since 1990 compared with the 2010 NECD ceilings (%) Greece Portugal Spain Belgium Ireland Sweden Austria France Netherlands EU15 Italy Finland Luxembourg United Kingdom Denmark Germany -100% -80% -60% -40% -20% 0% 20% NECD Target Figure 5b: Change in New EU-12 national SO 2 emissions since 1990 compared with the 2010 NECD ceilings (%) Cyprus Romania Malta Bulgaria Poland New EU12 Estonia Slovenia Lithuania Slovakia Hungary Czech Republic Latvia -100% -80% -60% -40% -20% 0% 20% NECD Target 14

15 Figure 5c: Change in national SO 2 emissions since 1990 compared with the 2010 Gothenburg ceilings CC-3 and EFTA-4 (%) FYR of Macedonia 492% -> Turkey CC3 Norway Liechtenstein Switzerland Croatia -70% -50% -30% -10% 10% 30% 50% 70% : CLRTAP Gothenburg Protocol Notes: Data for Iceland not available. Turkey and FYR of Macedonia have not signed the Gothenburg Protocol and hence do not have ceilings assigned. Figure 6a: Distance-to-target indicators (in index points) for the 2010 ceilings of the NECD, EU-15 Spain 12 Portugal 5 Greece 3 Ireland -4 Belgium -5 France Netherlands EU Italy United Kingdom Germany -22 Luxembourg -25 Austria Finland Sweden Denmark

16 Figure 6b: Distance-to-target indicators (in index points) for the 2010 NECD ceilings, New EU-12. Cyprus Malta 9 11 Bulgaria Slovenia Poland Romania NewEU12 Slovakia Czech Republic Estonia Hungary -49 Lithuania -54 Latvia Figure 6c: Distance-to-target indicators (in index points) for the 2010 Gothenburg ceilings, EFTA-4 and CC-3 Croatia -20 Liechtenstein -53 Norway -11 Switzerland Notes: The distance-to-target indicator is a measure of how close the current emissions (2005) are to a linear path of emissions reductions from 1990 to the ceiling set in Data for Iceland are not available. 16

17 Assessment - In general strong progress in reducing SO 2 emissions has been made by countries. Thirteen of the EU-27 Member States have already reduced their national SO 2 emissions below the level of the emission ceilings set in the National Emission Ceilings Directive (NECD). The Member States which have already achieved their ceilings are: Austria, the Czech Republic, Denmark, Estonia, Finland, Hungary, Latvia, Lithuania, Luxembourg, Poland, Romania and Sweden. - A number of other Member States reported SO 2 emissions for the year 2005 that were close to their respective ceilings under the NECD. These countries are considered well on track towards meeting their emission ceilings in However, a small number of Member States still require relatively significant reductions in SO 2 emissions to be made if they are to meet their 2010 ceilings under the NECD. These Member States include Cyprus, Malta, Portugal and Spain. - The EFTA-4 and CC-3 countries are not members of the European Union and hence have no emission ceilings set under the NECD. However, Switzerland and Norway have ratified the Gothenburg Protocol, requiring them to reduce their emissions to the agreed ceiling specified in the protocol by Switzerland has already met its Gothenburg Protocol ceiling, whilst Norway, which has not yet met its national ceiling, is on track to do so. References EEA EMEP / CORINAIR Atmospheric Emission Inventory Guidebook European Environment Agency, EMEP (1998). "Transboundary Acidifying Air Pollution in Europe", Part 1: Estimated dispersion of acidifying and eutrophying compounds and comparison with observations. EMEP/MSC-W Report 1/98, July

18 Data Table 1: EEA-32 SO 2 emissions by sector (ktonnes) Change % Change % contribution to total change % -61% % -1% % -21% % 23% % -14% % 0% % -4% % -1% % 0% % 0% Unallocated % -21% EEA-32 Total % -100% Notes: The change and % change between 1990 and 2005 may not exactly equal to that calculated using the figures in Table 1 due to rounding. Data for Iceland not available. Table 2: EU-15 SO 2 emissions by sector (ktonnes) Change % Change % % % % % % % % -1 % contribution to total change 19

19 % % 0 Unallocated % 0 Total % -100 Table 3: New EU-12 SO 2 emissions by sector (ktonnes), Change % Change % contribution to total change % -55% % 0% % -22% % 61% % -19% % 0% % -2% % 0% % 0% % 0% Unallocated % -62% Total % -100% Table 4: EFTA-4 SO 2 emissions by sector (ktonnes), Change % Change % -4% % -4% % contribution to total change % -22% % -30% 20

20 % -18% % 0% % -13% % -9% % 0% % 0% Unallocated % 0% Total % -100% Notes: Data for Iceland not available. Table 5: CC-3 SO 2 emissions by sector (ktonnes), Change Change (%) % contribution to Change % 6% % 0% % 12% % 8% % 1% % 0% % -1% % 0% % 0% % 0% Unallocated % -127% Total % -100% 21

21 Table 6: SO 2 emissions by country (ktonnes) Austria Belgium Bulgaria Cyprus Czech Republic Denmark Estonia Finland France Germany Greece Hungary Iceland * NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA NO/NA Ireland Italy Latvia Lithuania Luxembourg Liechtenstein Malta Netherlands Norway Poland Portugal Romania

22 Slovakia Slovenia Spain Sweden Switzerland Turkey United Kingdom EEA EU Croatia FYR of Macedonia * Data not available for Iceland 23

23 Table 7: Absolute and percentage change in SO 2 emissions since 1990 and the percentage reductions required ( 2 ) to meet the 2010 NECD and CLRTAP emission ceilings for EEA-32 countries. Change (ktonnes) % Change : NECD ceiling (%) : CLRTAP Gothenburg Protocol ceiling (%) Austria % -47% -47% Belgium % -73% -71% Bulgaria % -58% -57% Cyprus 6 16% 7% - Czech Republic % -86% -85% Denmark % -69% -69% Estonia % -63% - Finland % -58% -55% France % -72% -70% Germany % -90% -90% Greece 42 9% 7% 12% Hungary % -50% -46% Iceland * Ireland % -77% -77% Italy % -74% -72% Latvia % 1% 7% Liechtenstein % - - Lithuania % -35% -35% Luxembourg % -73% -73% Malta % -72% - Netherlands % -74% -74% Norway % - -58% Poland % -56% -56% Portugal % -50% -46% Romania % -30% -30% Slovakia % -79% -79% Slovenia % -86% -86% Spain % -66% -64% Sweden % -38% -38% Switzerland % - -38% Turkey % - - United Kingdom % -84% -83% * Data not available for Iceland 2 The actual 2010 emission ceilings specified in the NECD and Gothenburg Protocol are expressed as absolute emissions of SO 2, NO x, NH 3 and NMVOC (in ktonnes). For the purposes of this indicator 1990 is considered as a base year and the percentage change to emissions to meet the ceilings is calculated. Reported emissions for past years may change reflecting e.g. updated and revised emission inventory guidance, and so the % reduction required to meet the CLRTAP and NECD targets as shown here may change slightly in the future. 25

24 Meta Data Technical Information 1. Data source: 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 Base data are available from the EEA Data Service ( and the EMEP web site ( Where necessary, gaps in reported data are filled by ETC/ACC using simple interpolation techniques (see 6). The final gap-filled data used in this indicator is available from the EEA Data Service ( 2. Description of the data: Emissions (national totals and sectoral data) of SO 2 in 1000 tonnes (ktonnes). 3. 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. Certain analyses also include data for the FYR of Macedonia and Croatia. 4. Temporal coverage: Methodology and frequency of data collection: Annual country emission inventory submissions to UNECE/LRTAP Convention/EMEP. Recommended methodologies for emission inventory estimation are compiled in the EMEP/CORINAIR Atmospheric Emission Inventory Guidebook 3rd edition, EEA, Copenhagen EEA (2007). 6. Methodology of data manipulation: EEA/ETC-ACC gap-filling methodology. To allow trend analysis where countries have not reported data for one or several years, data has been interpolated to derive annual emissions. If the reported data is missing either at the beginning or at the end of the time series period, the emission value has been considered to equal the first (or last) reported emission value. It is recognised that the use of gap-filling 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. Base data, reported in SNAP, draft NFR or NFR are aggregated into the following EEA sector codes to obtain a common reporting format across all countries and pollutants: - Energy industries : emissions from public heat and electricity generation, oil refining and production of solid fuels; - Fugitive emissions : Emissions from extraction and distribution of solid fossil fuels and geothermal energy; - : emissions from combustion processes used in the manufacturing industry including boilers, gas turbines and stationary engines; - : 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; - Off-road transport : railways, domestic shipping, certain aircraft movements, and non-road mobile machinery used in agriculture & forestry; - Other (energy-related) emissions principally occurring from fuel combustion in the services and household sectors; - : non-combustion related emissions mainly in the services and households sectors including activities such as paint application, dry-cleaning and other use of solvents; - : manure management, fertiliser application, field-burning of agricultural wastes - : incineration, waste-water management; - Unallocated : The difference between the reported national total and the sum of the sectors reported by a country. The unallocated sector corresponds to the difference between the reported national total and the sum of the reported sectors for a given pollutant / country / year combination. It can be either negative or positive. Inclusion of this additional sector means that the officially reported national totals do not require adjustment to ensure that they are consistent with the sum of the individual sectors reported by countries. The following table shows the conversion of Nomenclature for Reporting (NFR) sector codes used for reporting by countries into EEA sector codes: EEA classification NFR Emission Source Category 0 National totals National total 1 1A1 3 Industry (energy) 1A2 26

25 2 Fugitive emissions 1B 7 Road transport 1A3b 8 Other transport (non-road mobile machinery) 1A3 (exl 1A3b) 9 Industry processes B Other (energy) 1A4a, 1A4b, 1A4b(i), 1A4c(i), 1A5a 10 Other (non-energy) Energy industries (power and heat production) 1A1a 14 Unallocated Difference between national total and sum of sectors (1 10) Quality information 7. Strengths and weaknesses (at data level): Strength: officially reported data following agreed procedures and EMEP/CORINAIR Emission Inventory Guidebook (EEA 2007), e.g. regarding source sector split. Weakness: The incomplete reporting and resulting need to interpolate/extrapolate data may obscure some trends. 8. Reliability, accuracy, robustness, uncertainty: SO 2 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 1998). 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 9. Overall scoring: (1-3, 1=no major problems, 3=major reservations) Relevancy: 1 Accuracy: 2 Comparability over time: 2 Comparability over space: 2 Further work required: Countries should improve the completeness of the time series of their estimates (filling gaps) and reduce the amount of unallocated emissions. Further validation and checking is the responsibility of the country and needs especially to lead to improved detailed sectoral time series of emissions. There is also a need for further validation and checking of emission estimates within the framework of CLRTAP/EMEP and EEA/ETC-ACC activities. 27