Indicator Assessment

Emissions of ozone precursors

Indicator Assessment

Prod-ID: IND-23-en

Also known as: CSI 002 , APE 008

Published 25 Oct 2010 Last modified 11 May 2021

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Topics: Environment and health

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Emissions of all ground-level ozone precursor pollutants have decreased across the EEA-32 region between 1990 and 2008; nitrogen oxides (NO_X) by 34%, non-methane volatile organic compounds (NMVOCs) by 45%, carbon monoxide (CO) by 56% and methane (CH₄) by 26%.
This decrease has been achieved mainly as a result of the introduction of catalytic converters for vehicles. These changes have significantly reduced emissions of NO_X and CO from the road transport sector, the main source of ozone precursor emissions.
The EU-27 is still some way from meeting its 2010 target to reduce emissions of NO_X, one of the two ozone precursors (NO_X and NMVOC) for which emission limits exist under the EU's NEC Directive (NECD). Whilst total NMVOC emissions in the EU-27 were below the NECD limit in 2008, a number of individual Member States anticipate missing their ceilings for one or either of these two pollutants.
Of the three non-EU countries having emission ceilings set under the UNECE/CLRTAP Gothenburg protocol (Liechtenstein, Norway and Switzerland), all three countries reported NMVOC emissions in 2008 that were lower than their respective 2010 ceilings. However both Liechtenstein and Norway reported NO_x emissions in 2008 that were substantially higher than their respective 2010 ceilings.

This indicator is discontinued. No more assessments will be produced.

Emission trends of tropospheric (ground-level) ozone precursors (EEA member countries, EU-27)

Note: This chart shows past emission trends of nitrogen oxides (NOx), non-methane volatile organic compunds (NMVOC), carbon monoxide (CO) and methane (CH4) in the EEA-32 and EU-27 group of countries. In addition - for the EU-27 - the aggregated Member State 2010 emission ceilings for NOx and NMVOC are shown.

Data source:

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Change in emissions of nitrogen oxides compared with the 2010 NECD and Gothenburg protocol targets (EEA member countries)

Note: The reported change in nitrogen oxide emissions (NOx) for each country, 1990-2008, in comparison with the 2010 NECD and Gothenburg protocol targets.

Data source:

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Change in emissions of non-methane volatile organic compounds compared with the 2010 NECD and Gothenburg protocol targets (EEA member countries)

Note: The reported change in NMVOC emissions for each country, 1990-2008, in comparison with the 2010 NECD and Gothenburg protocol targets.

Data source:

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Change in CO emissions 1990-2008 (EEA member countries)

Note: The reported change in carbon monoxide (CO) emissions for each country, 1990-2008.

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Change in CH4 emissions 1990-2008 (EEA member countries)

Note: The reported change in methane (CH4) emissions for each country, 1990-2008.

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Emissions of tropospheric (ground-level) ozone precursors reduced across the EEA-32 region between 1990 and 2008 (Figure 1). The different precursor species contribute to ground-level ozone formation to differing extents, in general NO_X and NMVOC are considered the most important precursor species.

In most countries, reductions have occurred for both the two ozone precursors for which emission limits exist under the NEC Directive and UNECE Gothenburg protocol (NO_X and NMVOC) (Figure 2); detailed breakdowns of sectoral and national emissions of NO_X and NMVOC are given in the pollutant specific factsheets for these pollutants, together with assessments of the progress being made by countries towards meeting their respective 2010 emission ceiling limits..

Emissions of CO in 2008 were 30.8 kt in the EEA-32 group of countries compared to 69.8 kt in 1990, a reduction of 56%. Methane and NMVOC emissions also significantly reduced between 1990 and 2008, by 26% and 45% respectively. Emissions of nitrogen oxides have fallen from 18.2 kt in 1990 to 12.0 kt in 2008 (a 34% 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 NMVOCs 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 emission reduction of NO_X emissions between 2007 and 2008. For example, emissions of NO_X in the EEA-32 have fallen by 5% between 2007 and 2008, a significantly greater reduction than in the preceding years.

The National Emission Ceilings Directive (NECD) and Gothenburg protocol sets, for each of the EU-27 Member States, ceilings (i.e. limits) for the two main ozone precursors, NO_X and NMVOC, that must be met by 2010 ^[1]. The reported data shows that as of 2008, slightly more than half of the 27 Member States are not on track towards meeting their combined target for NO_X. Three Member States are not on track to achieve reduction targets for NMVOC (Figure 3). Several of the non-EU countries (ie. 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 emissions that lie above a linear target path to their 2010 NO_X ceilings. However all three countries appear on track to meet their respective NMVOC ceilings.

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

Emission trends of nitrogen oxides (NO_X)
Emission trends of non-methane volatile organic compounds (NMVOC)

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

Change in nitrogen oxides emissions for each sector between 1990 and 2008 (EEA member countries)

Note: Percentage change in nitrogen oxide (NOx) emissions for each sector between 1990 and 2008.

Data source:

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Change in non-methane volatile organic compound emissions for each sector between 1990 and 2008 (EEA member countries)

Note: Percentage change in non-methane volatile organic compound (NMVOC) emissions for each sector between 1990 and 2008.

Data source:

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Change in CO emissions for each sector 1990-2008 (EEA member countries)

Note: Percentage change in carbon monoxide (CO) emissions for each sector between 1990 and 2008.

Data source:

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Change in CH4 emissions for each sector 1990-2008 (EEA member countries)

Note: Percentage change in methane (CH4) emissions for each sector between 1990 and 2008.

Data source:

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Contribution to total change in nitrogen oxides emissions for each sector (EEA member countries)

Note: The contribution made by each sector to the total change in nitrogen oxide (NOx) emissions between 1990 and 2008.

Data source:

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Contribution to total change in non-methane volatile organic compound emissions for each sector (EEA member countries)

Note: The contribution made by each sector to the total change in non-methane volatile organic compounds (NMVOC) emissions between 1990 and 2008.

Data source:

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Contribution to total change in CO emissions for each sector (EEA member countries)

Note: The contribution made by each sector to the total change in carbon monoxide (CO) emissions between 1990 and 2008.

Data source:

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Sector contributions of ozone precursor emissions (EEA member countries)

Note: The contribution made by different sectors to emissions of the tropospheric (ground-level) ozone precursors.

Data source:

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Contribution to total change in CH4 emissions for each sector (EEA member countries)

Note: The contribution made by each sector to the total change in methane (CH4) emissions between 1990 and 2008.

Data source:

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In 2008, the most significant sources of the ozone precursor pollutants in the EEA-32 region were the 'Agriculture' (45% of CH₄ emissions), Solvent and Product Use' (36% of NMVOC emissions), and ‘Road Transport’ sources (40% of NO_X and 34% of CO emissions) (Figure 4). Emissions of the various ozone-precursor pollutants have decreased in all sectors since 1990 except in the ‘Waste’ (CO emissions +19%), ‘Solvent and Product Use’ (NO_X emissions ×2.7, CO emissions ×110), Non-road transport (CO emissions +8%, NOX emissions + 7%), and ‘Industrial Processes’ sectors (NMVOC emissions +44%) (Figure 5).

Within the EEA-32, the transport sector is clearly the dominant source of ozone precursor pollutants. Combined, emissions from 'Road Transport' and ‘Other Transport’ contribute 41% of CO emissions in the EEA-32, 55% of NO_X, and 22% 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 activity within this sector over the period. This sector alone has contributed 69% of the total reduction of CO emissions, 43% of NO_X reduction and 61% of NMVOC reduction (Figure 6). 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 NO_X from the fuel-combustion related sectors 'Energy Industries' and 'Industry (Energy)' have also decreased significantly, together contributing 35% of the total reduction of NO_X 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 NO_X burners), implementation of flue-gas abatement techniques (e.g. NO_X scrubbers and selective (SCR) and non-selective (SNCR) catalytic reduction techniques) and fuel-switching from coal to gas (which has led e.g. to increases in energy efficiency and lower rates of NO_X emissions).

Significant reductions have also been achieved in the 'Other (Non Energy)' sector, which accounts for 19%, 21% and 28% of the reductions in emissions of CO, NO_X and NMVOC respectively since 1990. This reflects, amongst other measures, the introduction and implementation of the Solvent Emissions and Paints Directives.

Supporting information

Indicator definition

This indicator tracks trends since 1990 in anthropogenic emissions of ozone precursor pollutants: nitrogen oxides (NO_X), 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)

Rationale

Justification for indicator selection

Emissions of non-methane volatile organic compounds (NMVOCs), nitrogen oxides, carbon monoxide and methane contribute to the formation of ground-level (tropospheric) ozone.

Ozone is a powerful oxidant and tropospheric ozone can have adverse effects on human health and ecosystems. It is a problem mainly during the summer months. High concentrations of ground-level ozone adversely affects the human respiratory system and there is evidence that long-term exposure accelerates the decline in lung function with age and may impair the development of lung function. Some people are more vulnerable to high concentrations than others, with the worst effects generally being seen in children, asthmatics and the elderly. High concentrations in the environment are harmful to crops and forests, decreasing yields, causing leaf damage and reducing disease resistance.

Detailed information on individual acidifying pollutant emissions may also be found in the accompanying indicator fact-sheets for nitrogen oxides and non-methane volatile organic compounds.

Scientific references

No rationale references available

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 NO_X 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, NO_X, 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 NO_Xand 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
	NO_X	NMVOC	NO_X	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.

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 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 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

NO_X emission estimates in Europe are thought to have an uncertainty of about ±20% (EMEP, 2010), as the NO_X 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 NO_X. 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.

Data sources

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)
National emissions reported to the UNFCCC and to the EU Greenhouse Gas Monitoring Mechanism
provided by Directorate-General for Environment (DG ENV) , United Nations Framework Convention on Climate Change (UNFCCC)

Other info

DPSIR: Pressure
Typology: Performance indicator (Type B - Does it matter?)

Indicator codes

CSI 002
APE 008

Frequency of updates

This indicator is discontinued. No more assessments will be produced.

EEA Contact Info info@eea.europa.eu

Permalinks

Permalink to this version: 775ac9c90b3ccb9260fc8b8609872be0
Permalink to latest version: IND-23-en

Older versions

26 Jan 2010 - Emissions of ozone precursors

19 Dec 2008 - Emissions of ozone precursors

07 Mar 2008 - Emissions of ozone precursors (version 1)

22 Dec 2006 - Emissions of ozone precursors (version 1)

21 Oct 2005 - Emissions of ozone precursors (version 1)

04 Oct 2004 - Emission of ozone precursors

01 Jun 2001 - Emission of ozone precursors

Geographic coverage

Austria Belgium Bulgaria 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

Temporal coverage

1990-2010

For references, please go to https://www.eea.europa.eu/data-and-maps/indicators/emissions-of-ozone-precursors-version-2/assessment or scan the QR code.

PDF generated on 18 Apr 2024, 05:21 PM

Dates

First draft created:

21 Sep 2010, 03:58 PM

Publish date:

25 Oct 2010, 01:25 PM

Last modified:

11 May 2021, 11:42 AM

Topics

Topics: Environment and health