Sources and emissions of air pollutants in Europe

Key messages

In 2020, emissions of all key air pollutants in the 27 Member States of the EU (EU-27) continued to decline, maintaining a trend seen since 2005. This was the case despite an increase in gross domestic product (GDP) over the same period.

Residential, commercial and institutional energy consumption was the principal source of particulate matter in 2020. The manufacturing and extractive industry was also a significant source, while agriculture was an equally important source of PM₁₀. Between 2005 and 2020, emissions of particulate matter, PM₁₀ and PM_2.5, fell by 30% and 32%, respectively.

Agriculture was the principal source of ammonia and methane in 2020, responsible for 94% and 56% of total emissions, respectively. Ammonia emissions fell by only 8% from 2005 to 2020. This was the lowest percentage reduction of all pollutants.

In 2020, road transport was the principal source of nitrogen oxides, responsible for 37% of emissions. Emissions of nitrogen oxides fell by 48% between 2005 and 2020.

The energy supply sector was the principal source of sulphur dioxide, responsible for 41% of emissions in 2020. Emissions of sulphur dioxide fell by 79% between 2005 and 2020.

The manufacturing and extractive industries, and the energy supply sector, were the principal sources of heavy metals emissions in 2020. Between 2005 and 2020, the largest reductions in emissions were nickel (64%) and arsenic (62%).

Policy context

In the EU, emissions of air pollutants are regulated under the National Emission Reduction Commitments Directive (Directive (EU) 2016/2284), the NEC Directive (EU, 2016). This is one of the legislative instruments that supports the goal of a toxic-free environment, as announced in the European Green Deal. It is particularly critical to achieving the 2030 targets related to air pollution in the zero pollution action plan.

From 2010 to 2019, Member State-specific emission ceilings were applicable for the following four pollutants: nitrogen oxides (NO_X), including nitrogen monoxide (NO) and nitrogen dioxide (NO₂); non-methane volatile organic compounds (NMVOCs); ammonia (NH₃); and sulphur dioxide (SO₂). In 2016, the scope of the NEC Directive was extended to include fine particulate matter (PM_2.5), a pollutant that has a significant impact on health. From 2020 to 2029, the directive’s emission reduction commitments mirror the commitments under the revised Gothenburg Protocol for EU Member States. From 2030 onwards, more ambitious commitments will apply.

Under the NEC Directive, Member States must report annual emissions inventory information from 1990, or, in the case of PM_2.5, from 2000. The most recent reported data are from 2020. The EEA produces annual briefings on the reporting status under the NEC Directive, that assess progress towards these legal obligations.

At the pan-European level, air emissions are regulated under the United Nations Economic Commission for Europe (UNECE) Convention on Long-range Transboundary Air Pollution (the Air Convention). Under the Air Convention, the amended Gothenburg Protocol sets emission reduction commitments from 2020 onwards for NO_X, NMVOCs, sulphur oxides (SO_X), PM_2.5 and NH₃.

Parties to the Air Convention must reduce their emissions to the levels set out in the Convention Protocols to which they are parties (the Gothenburg Protocol, the Heavy Metals Protocol, the Protocol on Persistent Organic Pollutants and the previous pollutant-specific protocols), and report on their emissions. The EEA compiles an annual EU emission inventory report under the Air Convention, in cooperation with the EU Member States and the European Commission.

Key air pollutants

Air pollutants may have a natural, an anthropogenic or a mixed origin, depending on their sources or the sources of their precursors. In addition, air pollutants may be categorised as primary or secondary. Primary pollutants are emitted directly to the atmosphere, whereas secondary pollutants are formed in the atmosphere from precursor pollutants through chemical reactions and microphysical processes.

Key primary air pollutants include: particulate matter (PM), black carbon (BC), sulphur oxides (SO_X), nitrogen oxides (NO_X), ammonia (NH₃), carbon monoxide (CO), methane (CH₄), non-methane volatile organic compounds, including benzene (NMVOCs) and certain metals and polycyclic aromatic hydrocarbons, including benzo[a]pyrene (BaP).

Key secondary air pollutants comprise: PM, ozone (O₃), nitrogen dioxide (NO₂) and several oxidised volatile organic compounds (VOCs). Key precursor gases for secondary PM are: sulphur dioxide (SO₂), NO_X, NH₃ and VOCs.

Ground-level ozone is formed from chemical reactions in the presence of sunlight following emissions of precursor gases, mainly NO_X, NMVOCs, CO and CH₄. These precursors can be of either natural or anthropogenic origin.

The following key air pollutants are analysed in this chapter:

Fine particulate matter or particulate matter with a diameter of 2.5 micras (µm) or less: PM_2.5
Particulate matter with a diameter of 10µm or less: PM₁₀
Black carbon: BC
Sulphur dioxide: SO₂
Nitrogen oxides: NO_X
Ammonia: NH₃
Carbon monoxide: CO
Methane: CH₄
Non-methane volatile organic compounds: NMVOCs
Benzo[a]pyrene: BaP
Arsenic: As
Cadmium: Cd
Lead: Pb
Mercury: Hg
Nickel: Ni

Trends in air pollutants emissions, 2005-2020

of all pollutants in the EU-27 declined in 2020, maintaining the overall downward trend observed since 2005. Figure 1 shows the trend in total emissions of the main air pollutants, indexed as a percentage of their value in the reference year 2005 and set against gross domestic product (GDP) as a percentage of the 2005 value.

From 2005 to 2020, emissions of particulate matter with a diameter of 10 micras (μm) or less (PM₁₀) and 2.5μm or less (PM_2.5) fell by 30% and 32%, respectively. Notably, ammonia (NH₃) had the lowest reduction in emissions of only 8% over this period. Ammonia is an important precursor gas that contributes to the formation of secondary particulate matter. Furthermore, emissions of methane (CH₄) declined by only 17%. CH₄ is a potent greenhouse gas that drives climate change and is also an ozone (O₃) precursor. The principal source of both NH₃ and CH₄ emissions is the agriculture sector.

By contrast, emissions of sulphur dioxide (SO₂) fell significantly from 2005 to 2020, with a decrease of 79%. This was mainly due to the reduced use of coal over the period. Major reductions were also seen for nitrogen oxides (NO_X), black carbon (BC), carbon monoxide (CO) and non-methane volatile organic compounds (NMVOCs), with declines of 48%, 46%, 42% and 31%, respectively.

Figure 1. 2005-2020 Trends in EU-27 emissions of NH₃, CH₄, primary PM₁₀, NMVOCs, primary PM_2.5, CO, BC, NOX and SO₂, as percentages of 2005 levels, set against EU-27 GDP as a percentage of 2005 GDP

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The EEA briefing ’National Emissions reduction Commitments Directive reporting status 2022’ summarises progress towards reducing emissions of key air pollutants regulated under EU legislation at the EU and Member State levels. The biggest challenge for the period 2020-2029 will be reducing ammonia emissions: 11 Member States need to further cut emission levels. Looking forward to 2030, almost two thirds of Member States will need to reduce emissions of ammonia, nitrogen oxides and fine particulate matter to meet their 2030 commitments.

Figure 2 shows trends in the total emissions of heavy metals and benzo[a]pyrene (BaP) in the EU-27, indexed as a percentage of their value in the reference year 2005 and set against EU-27 GDP as a percentage of the 2005 value. Emissions of nickel (Ni) and arsenic (As) fell by more than 60% (64% and 62%, respectively), while mercury (Hg), lead (Pb) and cadmium (Cd) emissions fell by 51%, 49% and 40%, respectively. Emissions of BaP fell by only 18%.

Figure 2. 2005-2020, Trends in EU-27 emissions of BaP, cadmium, lead, mercury, arsenic and nickel, as percentages of 2005 levels set against EU-27 GDP as a percentage of 2005 GDP

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During the period 2005-2020, emissions showed a significant absolute decoupling from economic activity. Absolute decoupling occurs when an environmental impact variable, such as air pollutant emissions, remains stable or decreases, while GDP increases, leading to lower emissions of key air pollutants for each unit of GDP produced annually.

Both Figures 1 and 2 show that EU-27 air pollutant emissions declined between 2005 and 2020, while EU-27 GDP increased. However, because of the lockdowns implemented to stop the spread of COVID-19, and the subsequent decrease in some economic activities, GDP fell in 2020. The greatest decoupling is seen for SO₂, followed by NO_X, BC, CO and certain metals (Ni, As and Hg).

The decoupling of emissions from economic activity may be the result of a combination of factors, such as increased regulation and policy implementation, fuel switching, technological improvements and improvements in energy or process efficiencies. The increase in the EU’s consumption of goods produced outside the EU also plays a role in falling domestic emissions.

Main sources of air pollutants in 2020

The economic sectors that are the upstream sources of air pollutant emissions vary by pollutant. Figure 3 depicts the contributions of the main source sectors to the emissions of key air pollutants in the EU-27 in 2020.

The primary source of particulate matter, both PM10 and PM2.5, was energy consumption in the residential, commercial and institutional sector. It was responsible for 44% and 58% of emissions, respectively. The manufacturing and extractive industry, and the road transport sector, were also significant sources of both pollutants, while agriculture was an important source of PM10.

The agriculture sector was the principal source of NH3, responsible for 94% of emissions.

The agriculture sector also contributed more than half, 56%, of all CH4 emissions. The waste sector was the second-largest source of CH4 at 27%.

The road transport sector was the main source of emissions of NOX emissions, responsible for 37%, followed by agriculture at 19%, and the manufacturing and extractive industry at 15%.

Energy consumption in the residential, commercial and institutional sector was the main source of CO and BC emissions, contributing to 46% and 37% of total emissions, respectively.

The manufacturing and extractive industry sector was the main source of NMVOCs, responsible for 47% of emissions. Agriculture was the second-largest contributor at 27%.

Energy supply was the principal source of SO2 emissions at 41%, with the manufacturing and extractive industry sector being the second-largest contributor at 37%

Figure 3. Contributions to EU-27 emissions of BC, CO, NH3, NMVOCs, NOX, primary PM10, primary PM2.5, SO2 and CH4 from the main source sectors in 2020

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Figure 4 shows the contribution that the main source sectors made to EU-27 emissions of heavy metals and BaP in 2020.

The manufacturing and extractive industry sector was the principal source of all heavy metal emissions, except nickel. This sector was responsible for 60% of lead, 54% of cadmium, 44% of mercury and 42% of arsenic emissions.

For arsenic and mercury, the energy supply sector was the second-largest source of emissions, responsible for 39% and 38% of total emissions, respectively. The residential, commercial and institutional sector was the third most important for both pollutants at less than 10%.

For lead, the second-largest source of emissions was road transport, at 17% of emissions, followed by the residential, commercial and institutional sector, at 12% of emissions.

For cadmium, the residential, commercial and institutional sector, and the energy supply sector, were the second and third most important sources, responsible for 22% and 15% of total emissions, respectively.

The energy supply sector was the main source of nickel emissions, responsible for 42%, with the manufacturing and extractive industry sector, and the non-road transport sector, contributing 27% and 18% of emissions, respectively.

The residential, commercial and institutional sector was the primary source of BaP emissions, responsible for 85%.

Figure 4. Contributions to EU-27 emissions of arsenic, BaP, cadmium, mercury, nickel and lead from the main source sectors in 2020

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The data presented have been directly reported by Member States and do not include corrections that took place during the inventory review in 2022 by the European Commission on data reported for 2020. These corrections are highly unlikely to have an impact on the aggregated EU emission levels, but in some cases, they might alter national emissions levels.
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Sources and emissions of air pollutants in Europe

Key messages

Trends in air pollutants emissions, 2005-2020

Figure 1. 2005-2020 Trends in EU-27 emissions of NH3, CH4, primary PM10, NMVOCs, primary PM2.5, CO, BC, NOX and SO2, as percentages of 2005 levels, set against EU-27 GDP as a percentage of 2005 GDP

Figure 2. 2005-2020, Trends in EU-27 emissions of BaP, cadmium, lead, mercury, arsenic and nickel, as percentages of 2005 levels set against EU-27 GDP as a percentage of 2005 GDP

Main sources of air pollutants in 2020

Figure 3. Contributions to EU-27 emissions of BC, CO, NH3, NMVOCs, NOX, primary PM10, primary PM2.5, SO2 and CH4 from the main source sectors in 2020

Figure 4. Contributions to EU-27 emissions of arsenic, BaP, cadmium, mercury, nickel and lead from the main source sectors in 2020

Figure 1. 2005-2020 Trends in EU-27 emissions of NH₃, CH₄, primary PM₁₀, NMVOCs, primary PM_2.5, CO, BC, NOX and SO₂, as percentages of 2005 levels, set against EU-27 GDP as a percentage of 2005 GDP