Chapter 10.2 - Gridded Data

Last updated on 29 Aug 2019 09:29 (cf. Authors)

Information on spatial distribution of emissions is important for a number of questions in the field of air quality monitoring. Calculated data are used as input data for dispersion modelling of air pollutants or for visualizing the spatial distribution structure of emissions showing if abatement strategies were successful. For this reason, an ESRI ArcGIS based software has been developed which allows the UBA, independently and on the basis of information generally available, to regularly generate regionalized emission data sets for the complete area of the Federal Republic of Germany.

The software is documented in detail and complies with high standards as to flexibility and extensibility (description of the gridding tool).

Following pollutants are actually considered: NOx, NH3, SO2, CO, NMVOC, PM2.5 and PM10 (and TSP).

Gridded emissions of heavy metals and persistent organic pollutants will be added in future.


  • The gridding tool GRETA contains a complete set of the required data per base year. This includes emissions, distribution parameters, geometric data sets as well as the necessary definitions and allocation tables. The year 2010 was set as the reference year for which all the necessary data for the Gridding Tool was prepared. Furthermore, for the years before the year 2000 data sets have been adjusted.
  • Furthermore, the conditions of the current calculation have to be defined (for example PRTR data for point sources or TREMOD data for the traffic sector). Additionally, the relevant distribution parameters per source group or NFR sector to the spatial distribution of the emissions have to be allocated.
  • The PRTR emissions are checked against national totals and subtracted from the totals. National emissions, which are not covered by the PRTR point sources, are calculated per NFR sector. For each NFR sector, the spatial distribution of the national emissions takes place via distribution parameters, if possible as point sources (PQ) and line sources (LQ). The remaining emissions are spatially assigned to distribution parameters on district level and further, taking into account land cover data, on area level (FQ).
  • The calculation can be carried out for different arbitrary grid widths and different coordinate reference systems.

The results are available via the Central Data Repository CDR maintained of the EEA/EIONET.

Results with the EMEP grid

The spatial resolution of reported emissions changed from 50 km x 50 km EMEP grid to 0.1° × 0.1° long-lat in a geographic coordinate system (WGS84) to improve the quality of monitoring. The new EMEP domain covers the geographic area between 30°N-82°N latitude and 30°W-90°E longitude. More information about the grid development is available under EMEP grid.

As an example the following figures show the SO2 emission trend with the former rough EMEP grid. The annual emission height differs due to the different emission inventory submissions.

Previous results of SO2 emissions for the years 1990, 1995, 2000 and 2005 with the former grid size (submission 2012).

Actual results applying the new grid size

Acidification, eutrophication and Ground-level Ozone pollutants: Sulphur (SO2), nitrogen oxides (NOx), carbon monoxide (CO) and ammonia (NH3) and volatile organic compounds (VOCs).

The significant emission reduction history can be visualized by the following grid maps for the years 1990, 1995, 2000, 2005, 2010, 2015 and 2017. From 2000 ownwards information about point sources is available from the German PRTR or EPER. For the earlier years 1990 and 1995, information from point sources were transferred from EPER data of the year 2001 and their emissions were scaled accordingly.

By the presentation of the spatially distributed emissions the emission hotspots can be precisely identified for all pollutants. In general, these are located in the German cities (eg Berlin, Munich or Hamburg) or the conurbations (district of the Rhine-Ruhr area).

The reduction measures of SO2 emissions are a success story in itself. In the early 1970s, the use of flue gas desulphurization plants in coal-fired power plants and later brown coal power plants led to a significant SO2 decrease in the air. Since the 1990s, this reduction process has been further advanced by the use of low-sulfur fuels, so that today only a few areas are contaminated with SO2.

NOx and CO emissions are not only generated in the energy but also in the transport sector. This can be clearly seen in the graphic where road network is shown.

The outcome of the distribution of NMVOC emissions appears similar to the SO2 emissions. The main emitters are the industrial process sector and agriculture. The latter is mainly assigned to area and not to point sources.
Compared to the above mentioned air pollutants, drastic reduction of ammonia emissions did not occur in the last decades and abatement measures are still a political issue. The highest ammonia emissions occur in rural areas, especially in the north-west of Germany. The emissions from intensive livestock farming (point sources) are clearly visible in the graphics

Particle and fine particle emissions
With a decision of the Member States in 2006, PM10 and PM2.5 emissions for the years before 2000 are not mandatory in the reporting. In the 1990s, the sampling and analysis of particulate matter differed widely and a comparability was therefore not given. For this reason, the data were only scaled back to 1995.
For PM2.5 and TSP, the point source emissions are calculated via the emission ratio between PM10 and TSP / PM2.5 sector by sector.

Corresponding to the SO2 emissions, particulate matter emissions could be reduced by additional built-in filters in the power plants as well as in traffic.

Next section: 14. Adjustments and Emission Ceiling Exceedance

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