Indicator Assessment

Emissions of air pollutants from transport

Indicator Assessment
Prod-ID: IND-112-en
  Also known as: TERM 003
Published 04 Feb 2013 Last modified 11 May 2021
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Between 2009 and 2010, all air pollutant emissions from transport, except NOx, decreased (ranging between 2.5 % and 10 %). During the period 1990 to 2010, the main pollutants that contribute to acidification and particulate and ozone formation have shown a decreasing trend in emissions in the EEA‑32 (with fluctuations in some years). The largest percentage decreases over this period have been for CO (76 %) and non-methane volatile organic compound (NMVOC) (75 %). However, increases in shipping activity since 1990 have offset some of the reductions elsewhere, in particular for SOx, but also for NOx and PM. International shipping currently contributes to nearly 87 % of all transport SOx emissions. The rise of road freight transport explaines most of the increase in NOx in 2010.

Trend in emissions of air pollutants from transport in EEA-32

Note: Transport emissions of PM2.5, CO, SOx, NMVOC, NOx in EEA member countries.

The contribution of the transport sector to total emissions of the main air pollutants in 2009 (EEA-32)

Note: The graphs report the percentage contribution of transport and not transport sector to total emission of air pollutants in EEA32. Transport sector includes road transport, shipping, aviation and railways.

Transport is one of the main sources of air pollution in Europe, particularly in cities and urban areas such as towns, airports and sea ports. Key air pollutants emitted from combustion engines in all modes of transport include NOx, PM, CO, and VOCs. However, non-exhaust emissions of PM are also released due to the mechanical wear of brakes, tyres and road surfaces, and are not currently regulated. Emissions of VOCs also come from gasoline evaporation during refuelling and from vehicle and fuel storage tanks.

The Figure shows the trend in emissions of most pollutants from transport in EEA‑32 member countries since 1990. Emissions of different pollutants have been falling but at different rates. The decline has occurred in spite of a growth in transport activities reflected by various indicators such as energy consumption and passenger and freight transport volumes since 1990. The downward trend for most pollutants has followed the progressive introduction of tighter Euro emission standards on new road vehicles supplemented by improvements in fuel quality driven by EU Fuel Quality Directives. Tighter regulations in emissions from new diesel engines for railway locomotives and the sulphur content of marine fuels have also contributed to this downward trend in emissions in more recent years. The trends in emissions of key pollutants NOx and PM2.5 have been tempered by the increased market penetration of diesel vehicles since 1990. Diesel vehicles generally emit more of these pollutants per kilometre than their gasoline equivalents, particularly black carbon which has impacts on health and the climate but also NO2.

Supporting information

Indicator definition

This indicator is based on the assessment of emissions trends of CO, NOx, NMVOCs, SOx and primary particulates. 


Emissions are expressed as a percentage of 1990 levels (except for PM emissions, which are expressed as a percentage of 2000 levels).


Policy context and targets

Context description

Directive 2008/50/EC (EC, 2008) sets limit values for the atmospheric concentrations of the main pollutants, including sulphur dioxide (SO2), nitrogen dioxide (NO2), airborne PM (PM10 and PM2.5), lead, CO, benzene and ozone (O3) for EU Member States. These limits are related to transport implicitly, but the introduction of progressively stricter Euro emissions standards and fuel quality standards has led to substantial reductions in air pollutant emissions. Policies aimed at reducing fuel consumption in the transport sector, to cut greenhouse gas emissions, may also help to further reduce air pollutant emissions.

Iceland, Liechtenstein, Norway, Switzerland and Turkey are not members of the EU and hence have no emission ceilings set under the revised National Emission Ceilings Directive (NECD), Directive (EU) 2016/2284. As well as most of the EU Member States, Norway and Switzerland have ratified the 1999 United Nations Economic Commission for Europe (UNECE) Convention on Long-Range Transboundary Air Pollution (LRTAP) Gothenburg Protocol, which required them to reduce their emissions to the agreed ceiling, specified in the protocol, by 2010. Liechtenstein has also signed, but has not ratified, the protocol.


Both the NECD and the Gothenburg Protocol set reduction targets for SO2, NOx, NMVOCs and NH3 for the EEA-33 member countries. There are substantial differences in emission ceilings and, hence, emission reduction percentages for different countries, due to the different sensitivities of the ecosystems affected and the technical feasibility of making reductions.

Related policy documents



Methodology for indicator calculation

For air pollutants, data officially reported to the European Monitoring and Evaluation Programme (EMEP)/LRTAP Convention have been used. According to reporting requirements, emission figures for all pollutants are available from 1990, and for PM2.5, PM10 and total suspended particles (TSP) from 2000.

Methodology for gap filling

Where a complete time series of emission data has not been reported, data have been gap filled according to the methodologies of the European Environment Agency's (EEA's) European Topic Centre on Air and Climate Change (ETC/ACC). Details of the gap-filling procedure for the air pollutant data set are described in the EU emission inventory report 1990-2017 under the UNECE's Convention on LRTAP (EEA Technical Report No 8/2019).

Methodology references

  • EU emission inventory report European Union emission inventory report 1990-2017 under the UNECE Convention on Long-range Transboundary Air Pollution (LRTAP) , EEA Technical report No 8/2019.


Methodology uncertainty

Interpolation/extrapolation procedures are used to gap fill the underlying emission data set.

Data sets uncertainty

For the quantification of uncertainty, the EU LRTAP emissions inventory requires that Member States provide detailed information on uncertainties related to reported emissions data.

Rationale uncertainty

No uncertainty has been specified

Data sources

Other info

DPSIR: Pressure
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • TERM 003
Frequency of updates
Updates are scheduled once per year
EEA Contact Info


Geographic coverage

Temporal coverage