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Indicator Assessment

Emissions of acidifying substances (version 1)

Indicator Assessment
Prod-ID: IND-5-en
  Also known as: CSI 001
Published 07 Mar 2008 Last modified 11 May 2021
15 min read
This is an old version, kept for reference only.

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This page was archived on 25 Aug 2017 with reason: A new version has been published

Aggregated emissions of acidifying gases (NH3, NOx, SO2) have decreased significantly in most EEA member countries between 1990 and 2005 (Figure 1) despite increased economic activity (GDP) occurring during this period. However, meeting the 2010 NOx emission ceilings is likely to be a problem for a number of countries.

Emissions in the EU-15 Member States decreased by 47% since 1990 from 1 025 kt to 539 kt (Figure 2). The EU-15 is well on track on meeting its overall 2010 NECD target for acidifying pollutants.

Between 1900 and 2005 emissions of acidifying pollutants in the new EU-12 countries declined significantly from 503 kt to 206 kt, a reduction of 59% (Figure 3).  The new EU-12 is also on track on meeting its overall 2010 NECD target for acidifying substances.

Change in emissions of acidifying substances compared with the 2010 NECD targets (EEA member countries)

Note: Gothenburg targets are applied for countries without a NEC Directive target.

Data source:

Data from 2007 officially reported national total and sectoral emissions to UNECE/EMEP Convention on Long-Range Transboundary Atmospheric Pollution.

Emissions of acidifying gases have decreased significantly in most EEA member countries, with the highest reductions in Czech Republic and Latvia (Figure 4). However, emissions of acidifying pollutants have increased in Greece, Cyprus and Turkey between 1990 and 2005.  A recent study performed for the European Commission (http://ec.europa.eu/environment/air/pollutants/nationalprogr_dir200181.htm) indicates that 10 out of 23 EU-27 countries (excluding Greece, Romania, Bulgaria and Luxemburg) predict that their 2010 emission estimates will be higher than their NECD target value for NOx under implemented and planned policies and measures. Only 1 out of 23 Member States predicted that they will not meet their SO2 NECD target in 2010.

In the EU-15, emissions decreased by 47% between 1990 and 2005, mainly as a result of reductions in sulphur dioxide emissions, which contributed 76% of the total reduction of acidifying pollutants. Emissions from the energy, industry and transport sectors have all been significantly reduced, and contributed 61%, 17% and 17%, respectively, of the total reduction in weighted acidifying gas emissions. This reduction is mainly due to fuel switching to natural gas, economic restructuring of the new Lander in Germany and the introduction of flue gas desulphurisation in a number of power plants. So far, the reductions have resulted in the EU-15 being on track to reaching the overall target for reducing acidifying emissions in 2010. However, 9 out of 13 EU-15 Member States (excluding Greece and Luxemburg) indicated that there are unlikely to meet their NECD ceiling for NOx or SO2 (http://ec.europa.eu/environment/air/pollutants/nationalprogr_dir200181.htm).

Emissions of acidifying gases have also decreased significantly in the new EU-12 where emissions decreased by 59% between 1990 and 2005, mainly as a result of the large reduction in sulphur dioxide emissions, as in the EU-15 countries. Nine out of 10 new EU-12 countries (excluding Bulgaria, Romania) are well on track of meeting their NECD target for SO2 or NOx (http://ec.europa.eu/environment/air/pollutants/nationalprogr_dir200181.htm). 
The reduction in emissions of nitrogen oxides is due to abatement measures in road transport and large combustion plants.

Distance-to-target for EU-27 Member States

Note: The DTI results are shown in red (positive result ie

Data source:

Data from 2007 officially reported national total and sectoral emissions to UNECE/EMEP Convention on Long-Range Transboundary Atmospheric Pollution.

Sector split of emissions of acidifying pollutants (EEA member countries; EU-15; EU-27 - EU-15; EFTA-4 and CC-3)

Note: N/A

Data source:

Data from 2007 officially reported national total and sectoral emissions to UNECE/EMEP Convention on Long-Range Transboundary Atmospheric Pollution.

Contribution to total change in acidifying pollutant emissions for each sector and pollutant (EEA member countries)

Note: Contribution to change plots show the contribution to the total emission change between 1990-2005 made by a specified sector/ pollutant

Data source:

Data from 2007 officially reported national total and sectoral emissions to UNECE/EMEP Convention on Long-Range Transboundary Atmospheric Pollution.

Contribution to total change in acidifying pollutant emissions for each sector and pollutant (EU-15)

Note: Contribution to change plots show the contribution to the total emission change between 1990-2002 made by a specified sector/pollutant.

Data source:

Data from 2007 officially reported national total and sectoral emissions to UNECE/EMEP Convention on Long-Range Transboundary Atmospheric Pollution.

Contribution to total change in acidifying pollutant emissions for each sector and pollutant (EU-27 - EU-15).

Note: Contribution to change plots show the contribution to the total emission change between 1990-2005 made by a specified sector/ pollutant

Data source:

Data from 2007 officially reported national total and sectoral emissions to UNECE/EMEP Convention on Long-Range Transboundary Atmospheric Pollution.

Since 1990, the largest absolute decrease in emissions within the EU-15 has occurred in the 'energy industries' sector, which contributed 51% of the total reduction in emissions of acidifying substances (Figure 8). The most significant EU-15 emission sources in 2005 were 'agriculture' (34% of total emissions), 'energy industries' (24% of total emissions), 'road transport' (16% of total emissions) and 'energy use in industry' (10%). In 2005, the EU-15 relative weighted contribution to acidification from SO2 emissions was 28%, NOx emissions 37% and NH3 emissions 35%. Emissions of nitrogen oxide have fallen since 1990 due to abatement measures in road transport and large combustion plants, but these have to some extent been offset by increased road traffic. Ammonia emissions in the EU-15 are stabilising although agriculture emissions (the major source) are difficult to control and to quantify and hence are subject to high uncertainty.

The new EU-12 has experienced a similar percentage reduction of emissions since 1990 from the energy industries as in the EU-15, with 47% of the total reduction in the new EU-12 emissions of acidifying substances occurring from the energy industries sector  (Figure 9). Over the same period, emissions from the combustion-related emissions from industry and agriculture sectors have also decreased significantly. In 2005, the most significant new EU-12 sources were 'energy industries' (42% of total emissions), 'agriculture' (22% of total emissions), 'industry energy' (11% of total emissions), and 'road transport' and 'other transport' (13% of total emissions). In 2005, the new EU-12 relative weighted contribution of SO2 emissions was 53%, NOx was 23% and NH3 emissions contribution was 24%.

Supporting information

Indicator definition

The indicator tracks trends since 1990 in anthropogenic emissions of acidifying substances: Nitrogen oxides, ammonia, and sulphur dioxide, each weighted by their acidifying potential.

The indicator also provides information on emissions by sectors: Energy industries; road and other transport; industry (processes and energy); other (energy); fugitive emissions; waste; agriculture and other (non energy).

Units

ktonnes (acidifying equivalent)


 

Policy context and targets

Context description

Emission ceiling targets for NOx, SO2 and NH3 are specified in both the EU National Emission Ceilings Directive (NECD) [4] and the Gothenburg protocol under the United Nations Convention on Long-Range Transboundary Air Pollution (LRTAP Convention) (UNECE 1999). Emission reduction targets for the new EU-12 Member States have been specified in a consolidated version of the NECD for the EU-25 [1] which was adopted by the European Community after the accession of the EU-10 Member States. In addition, the consolidated NECD also includes emission ceilings for Bulgaria and Romania whose targets have been defined in their respective Accession treaties [2].

1. http://ec.europa.eu/environment/air/pdf/necd_consolidated.pdf

2. http://ec.europa.eu/environment/air/pdf/eu27_nat_emission_ceilings_2010.pdf

3. UNECE (1999). Protocol to the 1979 Convention on Long-Range Transboundary air pollution (LRTAP Convention) to abate acidification, eutrophication and ground-level ozone, Gothenburg, Sweden, 1 December 1999.

4. Directive 2001/81/EC, on national emissions ceilings (NECD) for certain atmospheric pollutants.

Targets

Emissions of NOx, SOx and NMVOCs 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 countries for the period 1990-2010.

Table 1. Percentage reduction required by 2010 from 1990 levels by country, for emissions of ozone precursors NOx and NMVOCs (emission targets weighted by ozone formation potential).

Country group

Country

NECD Targets 1990 - 2010

LRTAP Convention Gothenburg Protocol Targets 1990 - 2010

EU-15

Austria

-31%

-30%

EU-15

Belgium

-56%

-54%

EU-15

Denmark

-56%

-56%

EU-15

Finland

-48%

-46%

EU-15

France

-41%

-40%

EU-15

Germany

-74%

-73%

EU-15

Greece

7%

9%

EU-15

Ireland

-36%

-36%

EU-15

Italy

-51%

-51%

EU-15

Luxembourg

-35%

-35%

EU-15

Netherlands

-54%

-54%

EU-15

Portugal

-19%

-11%

EU-15

Spain

-46%

-45%

EU-15

Sweden

-35%

-35%

EU-15

United Kingdom

-70%

-69%

NewEU-12

Bulgaria

-38%

-36%

NewEU-12

Cyprus

30%

 

NewEU-12

Czech Republic

-77%

-75%

NewEU-12

Estonia

-47%

 

NewEU-12

Hungary

-43%

-39%

NewEU-12

Latvia

-4%

5%

NewEU-12

Lithuania

-19%

-19%

NewEU-12

Malta

-15%

 

NewEU-12

Poland

-43%

-43%

NewEU-12

Romania

2%

2%

NewEU-12

Slovakia

-66%

-66%

NewEU-12

Slovenia

-66%

-66%

 

EU-27

-51%

-53%

EFTA-4

Liechtenstein

-27%

-20%

EFTA-4

Norway

-17%

-26%

EFTA-4

Switzerland

-33%

-28%

CC3

Turkey

27%

-85%

Related policy documents

  • 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.
  • 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.
 

Methodology

Methodology for indicator calculation

Base data is available from http://webdab.emep.int/ and from the EEA dataservice (http://dataservice.eea.europa.eu/). Base data, reported in NFR are converted into the following EEA sector codes to obtain a common reporting format across all countries and pollutants:

 

-          Energy industry: Emissions from public heat and electricity generation

-          Fugitive emissions: Emissions from extraction and distribution of solid fossil fuels and geothermal energy

-          Industry (Energy): relates to emissions from combustion processes used in the manufacturing industry including boilers, gas turbines and stationary engines

-          Industry (Processes): Emissions from production processes

-          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;

-          Agriculture: manure management, fertiliser application, field-burning of agricultural wastes

-          Waste: incineration, waste-water management.

-          Other (energy-related) covers energy use principally in the services and household sectors

-          Other (Non Energy): Emissions from solvent and other product use.

 

The current Nomenclature for Reporting (NFR) reporting format used by countries includes 103 separate emission categories. The following table shows how these NFR categories are aggregated into EEA sector codes:

 EEA Code

EEA classification

NFR Emission Source Categories

0

National totals

National Total

1

Energy industries

1A1

3

Industry (Energy)

1A2

2

Fugitive emissions

1B

7

Road transport

1A3b

8

Other transport (non-road mobile machinery)

1A3 (excl 1A3b) + sectors mapped to 8 in table below

9

Industry (Processes)

2

4

Agriculture

4 + 5B

5

Waste

6

6

Other (Energy)

1A4a, 1A4b, 1A4b(i), 1A4c(i), 1A5a

10

Other (non-energy)

3 + 7

14

Unallocated

Difference between NT and sum of sectors (1-10)

12

Energy Industries (Power Production 1A1a)

1A1a

 

Where reported data from countries is incomplete, simple gap-filling techniques are used in order to obtain a consistent time-series (see following section). To obtain emission values for the acidifying substances, the gap-filled emission values are multiplied by an acidifying potential factor, (de Leeuw, 2002). The factors are NOx 0.02174, SO2 0.03125 and NH3 0.05882. Results are expressed in acidification equivalents ktonnes. For the main indicator trend graph, emissions are shown indexed to 1990 values (1990 emission =100). The sectoral shares are the share of the specific sector relative to the sum of all sectors for a given year. 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 they are consistent with the sum of the individual sectors reported by countries.

Methodology for gap filling

To allow trend analysis, where countries have not reported data for one or more years, data has been interpolated to derive the emissions for the missing year or years. If the reported data is missing either at the beginning or at the end of the period, the emission value is assumed to equal the first or last reported value. The use of gap-filling may 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. A list of the gap-filled dataset, plus a spreadsheet containing a record of the gap-filled data is available from EEA's dataservice (http://eea.eionet.europa.eu/Members/irc/eionet-circle/etcacc/library).

Methodology references

No methodology references available.

 

Uncertainties

Methodology uncertainty

The use of acidifying potential factors leads to some uncertainty. The factors are assumed to be representative for Europe as a whole; on the local scale different factors might be estimated. An extensive discussion on the uncertainties in these factors is available in de Leeuw (2002).

Data sets uncertainty

EEA uses data officially submitted by EU Member States and other EEA member countries which follow common guidelines on the calculation and reporting of emissions (EMEP/EEA 2006) [1] for the air pollutants NOx, SO2 and NH3.

Sulphur dioxide emission estimates in Europe are thought to have an uncertainty of about 10% as the sulphur emitted 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 and measured concentrations throughout Europe [2]. From these studies differences in the annual averages have been estimated in the order of 30% consistent with an inventory uncertainty of 10% (there are also uncertainties in the measurements and especially the modelling).

Nitrogen oxide emission estimates in Europe are thought to have an uncertainty of about 30%, 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 1998).  From these studies differences for individual monitoring stations of up to a factor of two have been found.  This is consistent with an inventory of national annual emissions having an uncertainty of 30% (there are also uncertainties in the measurements and especially the modelling).

Ammonia emissions are also relatively uncertain. Total uncertainty ranges in emission estimates have been estimated to be as much as 50% [3]. Emissions from the agricultural sector are also associated with considerable uncertainty. This is due to the complex interaction of many environmental and management factors that can lead to significant regional variations in emissions occurring and which may make the application of default emission factors imprecise.

[1] (EMEP/EEA 2006). EMEP/CORINAIR Emission Inventory Guidebook - 2006 (http://reports.eea.europa.eu/EMEPCORINAIR4/en/page002.html)

[2] 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 1998.

[3] Eggleston, H.S. (1998). Inventory Uncertainty and Inventory Quality, background paper. Expert Group meeting on Managing Uncertainty in National Greenhouse Gas Inventories; IPCC/OECD/IEA, Paris.

 

Rationale uncertainty

This indicator on emissions of acidifying pollutants is produced annually by EEA and is used regularly in its State of the Environment reporting. 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.

Data sources

Other info

DPSIR: Pressure
Typology: Performance indicator (Type B - Does it matter?)
Indicator codes
  • CSI 001
EEA Contact Info info@eea.europa.eu

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