NOx emissions and emission trends in Europe

Interactive maps

NOx emission trends

The emission trend for NOx was established for European countries from a combination of OMI-NO2 satellite data in conjunction with the LOTOS-EUROS chemistry transport model. The derived emission trends across the European domain are available as tend-maps and aggregated per country.

Over large areas of Europe a decrease of 2-6% per year is determined for the period 2005-2009. Largest emission reductions are observed for north western Spain. Comparison to the reported NOx emission changes (to EMEP in 2011) for the same period shows that the reported and determined emission changes are in general agreement with each other. The large decreases in emissions across north western Spain can be explained by the implementation of emission controls on the power plants in this region. These changes are not specifically included in current gridded emission inventories.

Illustration of the method used to compute trends in NOx emissions and NO2 columns over Europe.
See also (Curier et al, 2014).

Trend maps

Maps with trends in NOx emissions and columns over Europe.

Trends per country

Aggregation of trends per country.



Updates of point source database

Based on NOx emission trend analysis and an analysis of SO2 from point sources (Denier van der Gon et al., 2013) it is advised to update the large point source data on a more regular basis than in the current practice. Satellite data proved to be a useful tool to screen the source for suspects, as zooming into all point source locations separately is a tremendous task.

Improvement of emission inventory for Europe

Emission estimates derived from (inverse) model calculations provide an estimate for the total NOx emission in a grid cell or region. It is therefore difficult to use in an air quality assessment or forecast as crucial information is not available. Model assessments need emission data for the full mix of air pollutants on each locations in space and time. Hence, to acquire this level of detail sector and technology specific information is needed. Therefore, the recommendations of the evaluation exercise were incorporated into the update of the TNO/MACC-II emission inventory. As a part of a larger update the large point source emission fluxes are now incorporated with annually differentiated emissions. This is in contrast to the practice to keep the distribution among the large point sources constant for a five year period. The feedback loop to the emission inventory as enabled us to contribute to the improvement of model input data for Europe.


For more information on trend emissions, contact Bas Henzing at TNO.
For information on the TNO/MACC-II anthropogenic emissions, contact Hugo Denier van der Gon at TNO.


Curier, R.L., R. Kranenburg, A.J. Segers, R.M.A. Timmermans, M. Schaap.
Synergistic use of OMI NO2 tropospheric columns and LOTOS-EUROS to evaluate the NOx emission trends across Europe
Remote Sensing of Environment, Volume 149, June 2014, Pages 58-69, doi:10.1016/j.rse.2014.03.032

Hugo Denier van der Gon, Antoon Visschedijk, Chris McLinden, Vitali Fioletov, Len van der Wal.
Identification and cross-checking of large point source SO2 emissions in Europe using OMI retrievals
64th International Astronautical Congress, Beijing, China, 2013 (pdf)