Emissions of primary particles and secondary particulate matter precursors (CSI 003) - Assessment published Dec 2006

Indicator definition

This indicator tracks trends in emissions of primary particulate matter less than 10 mm (PM₁₀) and secondary precursors, aggregated according to the particulate formation potential of each precursor considered [1].

The indicator also provides information on changes in emissions from the main source sectors.

[1] de Leeuw, (2002), A set of emission indicators for long-range transboundary air pollution, Environmental Science & Policy, Volume 5, Issue 2, April 2002, Pages 135-145. (http://www.sciencedirect.com/science/article/B6VP6-44HYMJ7-1/1/d6e469ff7969874250c6d0f656a8c76b) (supported by the European Topic Centre on Air and Climate Change, under contract to the European Environment Agency)

Units

ktonnes (particulate formation potential)

Policy context and targets

Context description

There are no specific EU emission targets set for primary PM₁₀, as with respect to particulate emissions, measures are currently focused on controlling emissions of the secondary PM₁₀ precursors. However, there are several Directives and Protocols that affect the emissions of primary PM₁₀, including air quality standards for PM₁₀ in the First Daughter Directive to the Framework Directive on Ambient Air Quality and emission standards for specific mobile and stationary sources for primary PM₁₀ and secondary PM₁₀ precursor emissions.

For the particulate precursor species, emission ceiling targets for NO_x, SO₂ and NH₃ are specified in both the EU National Emission Ceilings Directive (NECD) 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

NECD. Directive 2001/81/EC, on National Emission Ceilings (NECD) for certain atmospheric pollutants.

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.

Targets

There are no specific EU emission targets for primary PM₁₀. However, emissions of the precursors NO_x, SO_x and NH₃ 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: Percentage reduction required by 2010 from 1990 levels by country, for emissions of the secondary particulate precursors NO_x, SO_x and NH₃ (emission targets weighted by particulate formation potential).

* Aggregated target for those New EU-12 Member States that have specified targets

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.
• 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

The dataset compiled by EEA/ETC-ACC for this indicator is from national total and sectoral emissions of PM₁₀, NO_x, SO₂ and NH₃ officially reported to UNECE/EMEP Convention on Long-Range Transboundary Atmospheric Pollution (LRTAP Convention).

Emissions data reported to the LRTAP Convention can be submitted in 3 different emission categories, SNAP, draft NFR or NFR. A detailed discription of the difference reporting formats can be found in the EMEP/CORINAIR Emission Inventory Guidebook - 2006 [1].

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

Methodology for gap filling

Where PM₁₀ data was not reported by countries to UNECE/EMEP, emission estimates for 1990, 1995, 2000 and 2005 were obtained from the RAINS PM₁₀ module, using the NEC_NAT_CLEV4 (NEC04) baseline scenario [1].

Where countries have not reported data for years apart from 1990, 1995, 2000 or 2005 data has been interpolated to derive annual 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. It is recognised that 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 will be made available from EEA's dataservice: http://dataservice.eea.europa.eu/dataservice/metadetails.asp?id=818

[1] http://www.iiasa.ac.at/web-apps/apd/gains/EU/index.login

Methodology references

• de Leeuw , F. (2002). A set of emission indicators for long-range transboundary air pollution. Environmental Science and Policy, Volume 5, Issue 2, p. 135-145. Abstract For assessing the progress made to mitigate the environmental problems related to long-range transboundary air pollution, emission indicators are developed for total potential acid, secondary PM 10 and ground-level ozone. The indicators are based on a weighted summation of emission data of the relevant precursors (SO 2 , NO x , NH 3 and VOC). By using comparable and reliable emissions data provided by the EU member states, the indicators provide clear information on the contribution of economic sectors and on the gap between current emissions and the emission targets set for 2010.
• EEA/ETC-ACC technical report describing the gap-filling methodologies used for the 2004 EEA/ETC-ACC LRTAP Convention and GHG (CRF) air emissions spreadsheet

Uncertainties

Methodology uncertainty

The use of particulate formation 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 pollutants PM₁₀, NO_x, NH₃ and SO₂.

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 (EMEP 1998) [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).

NO_x emission estimates in Europe are thought to have an uncertainty of about +/-30%, 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.  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).

The primary PM₁₀ data is likely to be very uncertain.

Incomplete reporting and resulting intra- and extrapolation may obscure some trends.

Rationale uncertainty

This indicator on emissions of particles 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.