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You are here: Home / Data and maps / Indicators / Emissions of ozone precursors / Emissions of ozone precursors (CSI 002/APE 008) - Assessment published Jun 2014

Emissions of ozone precursors (CSI 002/APE 008) - Assessment published Jun 2014

Indicator Assessment Created 04 Dec 2013 Published 27 Jun 2014 Last modified 27 Jun 2014, 02:12 PM

Generic metadata

Topics:

Air pollution Air pollution (Primary topic)

Agriculture Agriculture

Environment and health Environment and health

Tags:
methane | soer2010 | co | air pollution | csi | ozone precursors | ozone | nox | air emissions | nitrogen | emissions | air quality | air pollution indicators | acidification | pollution
DPSIR: Pressure
Typology: Performance indicator (Type B - Does it matter?)
Indicator codes
  • CSI 002
  • APE 008
Dynamic
Temporal coverage:
1990-2020
Geographic coverage:
Austria, Belgium, Bulgaria, Croatia, Cyprus, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom
 
Contents
 

Indicator definition

  • This indicator tracks trends since 1990 in anthropogenic emissions of ozone precursor pollutants: nitrogen oxides (NOX), carbon monoxide (CO), methane (CH4) and non methane volatile organic compounds (NMVOCs).
  • The indicator also provides information on emissions by sectors: 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)


Key policy question: What progress is being made in reducing emissions of ozone precursors across Europe?

Key messages

  • Emissions of the main ground-level ozone precursor pollutants have decreased across the EEA-33 region between 1990 and 2011; nitrogen oxides (NOX) by 44%, non-methane volatile organic compounds (NMVOC) by 57%, carbon monoxide (CO) by 61%, and methane (CH4) by 29%.
  • This decrease has been achieved mainly as a result of the introduction of catalytic converters for vehicles, which has significantly reduced emissions of NOX and CO from the road transport sector, the main source of ozone precursor emissions.
  • The EU-28 as a whole reported 2011 emissions at 4% below the 2010 NECD ceiling for NOX, one of the two ozone precursors (NOX and NMVOC) for which emission limits exist under the EU's NEC Directive (NECD). Total NMVOC emissions in the EU-28 were 22% below the 2010 NECD limit in 2011, however, seven of individual Member States did not meet their ceilings for one or both of these two pollutants.
  • Of the three non-EU countries having emission ceilings for 2010 set under the UNECE/CLRTAP Gothenburg protocol (Liechtenstein, Norway and Switzerland), all reported NMVOC emissions in 2011 that were lower than their respective ceilings, however Liechtenstein and Norway reported 2011 NOX emissions higher than their ceiling for 2010.

Change in emissions of nitrogen oxides compared with the 2010 NECD and Gothenburg protocol targets

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Change in emissions of non-methane volatile organic compounds compared with the 2010 NECD and 2010/2020 Gothenburg protocol targets

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Change in emissions of carbon monoxide

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Change in methane emissions

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Key assessment

Emissions of the main tropospheric (ground-level) ozone precursors reduced across the EEA-33 region between 1990 and 2011 (Figure 1). The different precursor species contribute to ground-level ozone formation to differing extents, but in general NOX and NMVOC are considered the most important precursor species.

In most countries, reductions in emissions have occurred since 1990 for both of the two ozone precursors for which emission limits exist under the NEC Directive and UNECE Gothenburg Protocol, NOX and NMVOC (Figures 2 and 3). Detailed breakdowns of sectoral and national emissions of NOX and NMVOC are given in the pollutant specific factsheets for these pollutants, together with assessments of the compliance of countries with their respective 2010 emissions ceiling limits, and progress being made meeting 2020 emission ceiling limits.

Emissions of CO in 2011 were 27.1 Mt in the EEA-33 group of countries compared to 70.3 Mt in 1990, a reduction of 61%. Methane and NMVOC emissions also significantly reduced between 1990 and 2011, by 29% and 57% respectively. Emissions of nitrogen oxides have fallen from 18.3 Mt in 1990 to 10.2 Mt in 2011 (a 44% reduction), mainly due to the introduction of three way catalytic converters for cars. The introduction of other European legislative measures has also contributed to the reduction of ozone precursors, such as reductions of NMVOC as a result of the implementation of the Solvent Emissions Directive in industrial processes. Further reasons for the observed reductions in emissions are provided in the 'Specific assessment' section of this indicator factsheet below.

The global recession that commenced mid-2008 has contributed to the overall reduction of ozone precursor emissions in recent years. For example, emissions of NOX in the EEA-33 fell by 7% per year on average in 2008 and 2009, in contrast to a 2% decrease per year in 2006 and 2007.

The National Emission Ceilings Directive (NECD) and Gothenburg Protocol set ceilings (i.e. limits) for each of the EU-28 Member States for the two main ozone precursors, NOX and NMVOC, that must have been met by 2010[1]. The reported data shows that seven of the 28 Member States reported 2011 emissions higher than their 2010 targets for NOX (APE001 - Figure 3), whilst only two Member States reported 2011 emissions higher than their 2010 ceiling for NMVOC (APE004 - Figure 3). Several of the non-EU countries (i.e. Liechtenstein[2], Norway and Switzerland) also have 2010 emissions ceilings defined under the Gothenburg protocol of the UNECE Convention on Long-range Transboundary Air Pollution. Of these countries, Liechtenstein and Norway have both reported 2011 emissions above their 2010 NOX ceilings, however all three countries' 2011 emissions were below their respective NMVOC ceilings.

The NECD protocol is currently being reviewed, as part of the implementation of the Thematic Strategy on Air Pollution, but a proposal for a revised directive is presently on hold until 2013. A revision of the Gothenburg protocol was published in June 2012, and proposed percentage emission reductions from 2005 levels to be met by 2020 for the four already regulated substances (NOX, NMVOC, SO2 and NH3) and in addition for primary emissions of PM2.5. Existing emission ceilings for 2010 have been extended to 2020 such that all countries have additional obligations to maintain emission levels below their 2010 ceilings, or to further reduce emissions if they have not yet met these ceilings.

Further details concerning emissions of the main ozone precursor pollutants may be found in the following indicator fact sheets:

[1] The NECD and Gothenburg protocol also set emission ceilings for two other pollutants ammonia (NH3) and sulphur dioxide (SO2) that contribute to acidification and particulate matter formation.

[2] Liechtenstein has signed, but not yet ratified, the Gothenburg protocol.

Specific policy question: How do different sectors and processes contribute to emissions of ozone precursors?

Sector split of emissions of ozone-precursor pollutants

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Change in nitrogen oxides emissions for each sector

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Change in non-methane volatile organic compounds emissions for each sector

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Change in carbon monoxide emissions for each sector

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Change in methane emissions for each sector

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Contribution to total change in nitrogen oxides emissions for each sector

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Contribution to total change in non-methane volatile organic compounds emissions for each sector

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Contribution to total change in carbon monoxide emissions for each sector

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Contribution to total change in methane emissions for each sector

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Specific assessment

In 2011, the most significant sources of ozone precursor pollutants in the EEA-33 region were the 'Agriculture' (48% of CH4 emissions), 'Solvent and product use' (43% of NMVOC emissions), and 'Road Transport' sources (40% of NOX and 26% of CO emissions) (Figure 6). Emissions of the various ozone-precursor pollutants have decreased across most sectors since 1990 (Figures 7 to 10).

Within the EEA-33, transport sectors are the dominant source of several ozone precursor pollutants. Combined, emissions from 'Road Transport' and 'Non-road Transport' contribute 29% of the total CO emissions in the EEA-33, 48% of NOX, and 17% of NMVOC.

Since 1990, the vast majority of the reduction of 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 75% of the total reduction of CO emissions, 47% of NOX reduction (Figure 11) and 52% of NMVOC reduction (Figure 12). The emission reductions have primarily been achieved as a result of fitting three way catalytic converters for petrol-fuelled cars (driven by the legislative Euro standards).

Emissions of NOX from the fuel-combustion related sectors 'Energy production and distribution' and 'Energy use in Industry' have also decreased significantly, together contributing 41% of the total reduction of NOX emissions since 1990. In this instance the reduction has been achieved as a result of measures including the introduction of combustion modification technologies (such as use of low NOX burners), implementation of flue-gas abatement techniques (e.g. NOX scrubbers and selective catalytic and non-catalytic reduction techniques, i.e. SCR and SNCR) and fuel-switching from coal to gas (which has led to, for example, increases in energy efficiency and lower rates of NOX emissions).

 

Data sources

Policy context and targets

Context description

Within the European Union, the National Emission Ceilings Directive (NEC Directive) imposes emission ceilings (or limits) for emissions of NOX and NMVOCs (the NEC Directive also sets emissions ceilings for ammonia NH3 and sulphur dioxide SO2). There are no specific EU emission targets set for either carbon monoxide (CO) or methane (CH4). However, there are several Directives and Protocols that affect the emissions of CO and CH4. Methane is included in the basket of six greenhouse gases under the Kyoto protocol (see CSI 010: Greenhouse gas emissions and removals).

Internationally, the issue of air pollution emissions is also being addressed by the UNECE Convention on Long-range Transboundary Air Pollution (the LRTAP Convention) and its protocols. 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. SO2, NOX, NH3 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.

Targets

Emissions of NOXand NMVOC 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.

Table: 2010 Targets under the NEC Directive and the Gothenburg Protocol, in kt

2010 NECD ceilings

2010 CLRTAP Gothenburg Protocol ceilings

 

NOX

NMVOC

NOX

NMVOC

Austria 103 159 107 159
Belgium 176 139 181 144
Bulgaria 247 175 266 185
Cyprus 23 14
Czech Republic 286 220 286 220
Denmark 127 85 127 85
Estonia 60 49
Finland 170 130 170 130
France 810 1050 860 1100
Germany 1051 995 1081 995
Greece 344 261 344 261
Hungary 198 137 198 137
Iceland*
Ireland 65 55 65 55
Italy 990 1159 1000 1159
Latvia 61 136 84 136
Liechtenstein 0.37 0.86
Lithuania 110 92 110 92
Luxembourg 11 9 11 9
Malta 8 12
Netherlands 260 185 266 191
Norway 156 195
Poland 879 800 879 800
Portugal 250 180 260 202
Romania 437 523 437 523
Slovakia 130 140 130 140
Slovenia 45 40 45 40
Spain 847 662 847 669
Switzerland 79 144
Sweden 148 241 148 241
Turkey*
United Kingdom 1167 1200 1181 1200

 

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

Related policy documents

  • 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.
  • Greenhouse gas monitoring mechanism
    Decision No 280/2004/EC of the European Parliament and of the Council of 11 February 2004 concerning a mechanism for monitoring Community greenhouse gas emissions and for implementing the Kyoto Protocol
  • 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 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 ETC/ACM using simple interpolation techniques (see below). The final gap-filled data used in this indicator are 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 & 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:

EEA classification

Non-GHGs (NFR)

GHG - CH4 (CRF)

National totals

National total

National totals without LUCF

Energy production and distribution

1A1, 1A3e, 1B

1A1

Energy use in industry

1A2

1A2

Road transport

1A3b

1A3b

Non-road transport (non-road mobile machinery)

1A3 (exl 1A3b)

1A3a, 1A3c, 1A3d, 1A3e

Industrial processes

2

2

Solvent and product use

3

Agriculture

4

4

Waste

6

6

Commercial, institutional and households

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

1A4, 1A5

Other

7

3 + 7

 

In addition to historic emissions, Figure 1 of the indicator factsheet also shows the latest 2010 projection estimates reported by the EU-27 Member States under the NEC Directive. The "with measures" (WM) projections reported by Member States take into account currently implemented and adopted policies and measures. Where countries have instead reported "business as usual" or "current legislation" projections, it is assumed for comparison purposes that these are equivalent to a WM projection. The "with additional measures" projections reported by Member States take into account additional future planned policies and measures but which are not yet implemented.

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 NOX, SOX, 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 are not yet complete and are 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

No methodology references available.

Uncertainties

Methodology uncertainty

The use of gap-filling for when countries have not reported emissions for one of 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

NMVOC emission estimates in Europe are thought to have an uncertainty of about ±30% due in part to the difficulty in obtaining good emission estimates for some sectors and partly due to the absence of good activity data for some sources. The 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

 

NOX emission estimates in Europe are thought to have an uncertainty of about ±20% (EMEP, 2010), as the NOX emitted comes both from the fuel burnt and the combustion 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 dataset used will have higher uncertainty. The 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

Uncertainties in emissions of CO are likely to have a similar magnitude of uncertainty as for NOX. NMVOC emissions data have been verified by EMEP and others by means of comparison between modelled and measured concentration throughout Europe. From these studies total uncertainty ranges have been estimated to about ±50%. Some main source categories are less uncertain.

CH4 estimates are reasonably reliable as they are based on a few well-known emission sources. The IPCC believes that the uncertainty in CH4 emission estimates from all sources, in Europe, is likely to be about ±20 %. CH4 emissions from some sources, such as rice fields, are much larger (possibly an order of magnitude), but are a minor emission source in Europe. In 2004, EU Member States reported uncertainties in their estimates of CH4 emissions from enteric fermentation as ranging between 0.5 % (UK) and 2.8 % (Ireland) of the total national GHG emissions (EEA 2004).

Rationale uncertainty

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

More information about this indicator

See this indicator specification for more details.

Contacts and ownership

EEA Contact Info

Martin Adams

Ownership

EEA Management Plan

2013 1.1.2 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled once per year
European Environment Agency (EEA)
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