Air pollution statistics - air emissions accounts

Data from December 2017. Most recent data: Further Eurostat information, Main tables and Database Next update of the article: January 2019

This article is about emissions of acidifying gases and ozone precursor substances classified by emitting economic activities. Eurostat records and publishes those in so-called air emissions accounts (AEA), one of the modules in the European environmental economic accounts (for which the legal basis is Regulation (EU) No 691/2011). AEA are suited for integrated environmental-economic analyses such as calculating emission intensities or 'footprints'.

In addition, Eurostat disseminates emissions of air pollutants classified by technical processes. These are recorded in so-called emission inventories for air pollutants and form the official data for international policies on transboundary air pollution. Thirdly, Eurostat estimates and disseminates so-called 'footprints' which are emissions of air pollutants classified by products that are finally demanded by households or government, or that are invested in or exported.

The EU-28 emissions of acidifying gases (sulphur dioxide (SO2), nitrogen oxides (NOx) and ammonia (NH3)) have been continuously decreasing over the past years. In 2015, emissions of NH3 and NOx contributed roughly 40 % each while sulphur dioxide contributed around 20 % to the total acidifying potential.

The EU-28 emissions of ozone precursors (nitrogen oxides (NOx), methane (CH4), carbon monoxide (CO) and non-methane volatile organic compounds (NMVOC)) have also been falling over the past years. In 2015 the main contributors to the tropospheric ozone formation potential were NOx and NMVOC with 57 % and 31 % respectively.

Main statistical findings

Acidifying gases

Figure 1: Emissions of acidifying gases, EU-28, 2008 - 2015
(thousand tonnes of SO2 equivalents) - Source: Eurostat (env_ac_ainah_r2)
Figure 2: Emissions of acidifying gases by economic activity, EU-28, 2010 and 2015
(% of total emissions in SO2 equivalents) - Source: Eurostat (env_ac_ainah_r2)
Figure 3: Emissions of acidifying gases by economic activity, EU-28, 2015
(thousand tonnes of SO2 equivalents) - Source: Eurostat (env_ac_ainah_r2)
Figure 4: Intensity of acidifying gas emissions by economic activity, EU-28, 2010 and 2015
(grammes of SO2 equivalents per EUR) - Source: Eurostat (env_ac_aeint_r2)

Several air pollutants contribute to the acidification of the environment. The most important ones are discussed in this article and comprise sulphur dioxide (SO2), nitrogen oxides (NOx) and ammonia (NH3). The impact of SO2, NOx and NH3 can be observed in the progressive degradation of soils, water and forests. They also contribute to the formation of fine particles in the air that cause respiratory diseases. The acidifying potential of SO2, NOx and NH3 is commonly measured in SO2 equivalents (SO2-eq.). The conversion factors are shown in Table 2.

In 2015, emissions of ammonia accounted for the highest share of the acidifying potential (41 % or 7.6 million tonnes of SO2-eq.) followed by nitrogen oxides (40 % or 7.4 million tonnes of SO2-eq.) and sulphur dioxide (19 % or 3.5 million tonnes of SO2-eq.). The emissions of acidifying gases decreased by 24 % between 2008 and 2015. This represents a reduction of 5.7 million tonnes of SO2-eq. emissions. Emissions of nitrogen oxides fell by 24 %, ammonia by 1 % and sulphur dioxide by 49 % (Figure 1).

Acidifying gas emissions by economic activity

Agriculture, forestry and fishing account for the largest share in all industries: In 2015, these activities contributed 43 % of total acidifying potential emitted by industries and households, compared with 37 % in 2010 (Figure 2). Ammonia is the largest contributor to the acidifying emissions from agriculture, forestry and fishing with 7.1 million tonnes of SO2-eq (Figure 3).

The second largest production activity in 2015 was transportation and storage with a share of 20 % or 3.6 million tonnes of SO2-eq., followed by the electricity, gas, steam and air conditioning supply industry (12 % or 2.3 million tonnes of SO2-eq.). While the largest share of emissions in transport came from NOx, in the electricity, gas, steam and air conditioning supply industry SO2 emissions were predominant (Figure 2 and 3).

Most activities recorded significant drops in acidifying emissions. The biggest decrease was observed in electricity, gas, steam and air conditioning supply industry, which dropped from 3.4 to 2.3 million tonnes of SO2-eq. (34 %) between 2010 and 2015. The more systematic use of end-of-pipe pollution filters and the use of more efficient combustion technologies in the electricity and heat production are the main contributors to this development. The only industry where emissions of acidifying gases slightly increased (by 1.4 %) between 2010 and 2015 was agriculture, forestry and fishing .

Intensity of acidifying gas emissions

The ratio of acidifying gas emissions in tonnes of SO2-eq. per million euros of gross value added (GVA) measures the intensity of acidifying gas emissions of industries (Figure 4). In 2015, agriculture, forestry and fishing showed the highest intensity with42.2 grammes per euro. This is due to the fact that the agriculture, forestry and fishing industry has large emissions of ammonia and has a comparatively low contribution to the GVA of the economy. Compared to the year 2010 the intensity of acidifying gas emissions decreased in all main industries. The biggest decrease was recorded for manufacturing industry (32 %), followed by electricity, gas and air conditioning supply (30 %).

Ozone precursors

Figure 5: Emissions of ozone precursors, EU-28, 2008 - 2015
(thousand tonnes of NMVOC equivalents ) - Source: Eurostat (env_ac_ainah_r2)
Figure 6: Emissions of ozone precursors by economic activity, EU-28, 2010 and 2015
(% of total emissions in NMVOC equivalents) - Source: Eurostat (env_ac_ainah_r2)
Figure 7: Intensity of ozone precursor emissions by economic activity, EU-28, 2010 and 2015
(grammes of NMVOC equivalents per EUR) - Source: Eurostat (env_ac_aeint_r2)

Tropospheric ozone occurs when so-called ozone precursor substances (i.e. non-methane volatile organic compounds (NMVOC), nitrogen oxides (NOx), carbon monoxide (CO) and methane (CH4)) react in the lower atmosphere in the presence of sunlight. High ozone levels occur during the warmer summer months as the sun makes for example exhaust fumes from vehicles react in the lower atmosphere. High ozone levels are known to damage human tissue and are a health risk, especially for people with respiratory problems. Through the National Emissions Ceilings Directive (NECD) and the Gothenburg Protocol under UNECE-CLRTAP, the EU focuses on the emissions of NOx and NMVOC as they are the most relevant of the four pollutants.

Emissions of ozone precursors in the EU fell between 2008 and 2015 for all pollutants (Figure 5). The emissions of NMVOC, NOx, CO and CH4 decreased by 22 % or 6.3 million tonnes of NMVOC equivalents (NMVOC-eq.). The main pollutants contributing to tropospheric ozone formation are NOx and NMVOC with 57 % and 31 % respectively (Figure 5). Between 2008 and 2015, the emissions of both NOx and CO fell by 24 % (or in absolute terms 4 million tonnes and 0.7 million tonnes of NMVOC-eq. respectively).

Ozone precursor emissions by economic activity

With 25 % private households have been the biggest contributor to total emissions of ozone precursors in 2015; closely followed by the transport industry with 24 % . The manufacturing industry is the third largest emitter with 19 % (Figure 6).

Between 2010 and 2015, the biggest absolute drop occurred in households (1 million tonnes of NMVOC-eq. or 17 %).

Ozone precursor emission intensities

Ozone precursor emission intensity is the ratio of ozone precursor emissions in tonnes of NMVOC equivalents per million euros of gross value added (GVA). Figure 7 shows that in 2015 agriculture, forestry and fishing (15.4 grammes NMVOC-eq. per euro) showed the highest intensity, followed by the transportation and storage industry. Compared to year 2010 the intensity decreased in all main industries except mining and quarrying. The biggest decrease was observed in manufacturing (21 %).

Data sources and availability

The basis for Eurostat’s air emissions accounts is Regulation (EU) No 691/2011 on European environmental economic accounts.

Annual data are transmitted by the EU Member States, as well as the European Free Trade Association (EFTA) countries and some candidate countries.

Emissions of individual acidifying gases and ozone precursor substances are converted and aggregated to provide information for the environmental pressures 'acidifying potential' and 'tropospheric ozone formation potential'. They use common units (SO2 equivalent and NMVOC equivalent) to allow comparison and combination of the relative effect of different gases. For calculating SO2 equivalents the following conversion factors are used: nitrogen oxides 0.7, sulphur dioxide 1.0 and ammonia 1.9. For calculating NMVOC equivalents the following conversion factors are used: nitrogen oxides 1.22, non-methane volatile organic compounds 1.0, carbon monoxide 0.11 and methane 0.014.

In air emissions accounts, the emissions data are organised by economic activity, using NACE. This makes it possible to have an integrated environmental-economic analysis to supplement national accounts. Economic activities encompass production by all businesses resident in a country, including those operating ships, aircraft and other transportation equipment in other countries.

Air emissions accounts also include households as consumers. Their emissions are accounted for whenever household consumption is directly responsible for environmental pressures. For example, emissions from a privately owned car are counted under households, whereas cars owned by transport businesses (such as taxis) are counted under transport services.

The following activity groupings are used in this article:

  • agriculture, forestry and fishing — NACE Rev. 2 Section A;
  • mining and quarrying — NACE Rev. 2 Section B;
  • manufacturing — NACE Rev. 2 Section C;
  • electricity, gas, steam and air conditioning supply — NACE Rev. 2 Section D;
  • transportation and storage — NACE Rev. 2 Section H;
  • other services, water supply and construction — NACE Rev. 2 Sections E to G and I to U, in other words all remaining economic activities as defined in NACE;
  • households — households as consumers.

Three perspectives of emission statistics for air pollutants

Eurostat presents three perspectives of emission statistics for air pollutants:

Perspective Statistical framework Purpose Related data set Related SE article
1. Emissions of air pollutants classified by economic activities Air Emissions Accounts (AEA) by Eurostat tailored for integrated environmental-economic analyses env_air_aa this article
2. Emissions of air pollutants classified by technical processes Emission inventories for air pollutants by UNECE official international reporting framework for CLRTAP env_air_emis link
3. 'footprints' = GHG emissions classified by final use of products Modelling results published by Eurostat one particular analytical application of AEA env_ac_io10 not available

Emissions accounts versus emission inventories

The main differences between air emissions accounts (AEA) and emission inventories for air pollutants are:

Air emissions accounts – air pollutants (residence principle) Emission inventories for air pollutants (territory principle)
Emissions are assigned to the country where the economic operator causing the emission is resident. Emissions are assigned to the country where the emission takes place
Emissions are classified by economic activity, following the NACE classification of the system of national accounts. Emissions are assigned to processes classified according to their technical nature (e.g. combustion in power plants, solvent use).
Emissions from international navigation and aviation are assigned to the countries where the operator of the ship/aircraft is resident, regardless of where the emission takes place. Emissions from international navigation and aviation are assigned to the countries where the associated fuel is bunkered, irrespective of the operator's place of residence.

Note: National and EU totals differ between the two approaches, as different boundaries apply. GHG inventories include international aviation and maritime transport (international bunker fuels) as memorandum items, which mean that they are excluded from national totals reported. However, they are included in air emissions accounts totals. Therefore total emissions reported in GHG inventory databases can differ significantly from the total reported in air emissions accounts for countries with a large international aircraft and/or shipping fleet. AEA reconciles totals with emission inventories through so-called 'bridging items'.

Context

The need to supplement information on the economy with environmental indicators has been recognised in a European Commission Communication titled 'GDP and beyond'COM(2009) 433). Furthermore, similar recommendations have been made within the Report by the Commission on the Measurement of Economic Performance and Social Progress,the so-called Stiglitz report. The recommendations support the expansion of the statistical understanding of human well-being by supplementing economic indicators such as GDP with additional information, including physical indicators related to the environment.

Air emissions accounts measure the interplay between the economy and the environment with respect to air emissions, in order to assess whether current production and consumption activities are on a sustainable path of development. Measuring sustainable development is a complex undertaking as it has to incorporate economic, social and environmental indicators. The data obtained from air emissions accounts may subsequently feed into political decision-making, underpinning policies that target both continued economic growth and sustainable development, for example, initiatives such as the Europe 2020 strategy, which aims to achieve a resource-efficient, low-carbon economy for the EU by 2020.

See also

Further Eurostat information

Publications

Database

env_ac_ainah_r2
env_ac_aibrid_r2

Dedicated section

Methodology / Metadata

Source data for tables and figures (MS Excel)

External links