About Topas

Exposure to environmental pollution is thought to cause as many as 9 million premature deaths each year. The largest health impacts are associated to air pollutants and particulate matter in particular. The latter is thought to cause an average reduction in life expectancy of 6-12 months in Europe. EU limit and target values are still exceeded throughout the EU. Moreover, a large proportion of the urban population (82-85% for PM2.5 and 50-62% for PM10) is exposed to concentrations above the WHO air quality guideline values. In short, air pollution has wide-ranging effects on human health and well-being and affect European competitiveness and sustainable growth.

Improving air quality in European cities will bring major health benefits. However, air pollution is a complex, multi-faceted problem. Uninformed mitigation efforts can unnecessary impact businesses and may impact society without achieving significant environmental impact. To understand the problem, to inform the public, fulfill reporting obligations and to cost-effectively reduce pollution it is imperative that authorities have accurate information on its origin and effectiveness of potential measures. The quantification of sectoral as well as natural contributions discriminating between local and long rage (transboundary) ones is of particular interest. However, so far no operational service was available providing users with the relevant daily information on source attribution. Current (experimental) methodologies are expensive, hard to intercompare, and generally provide limited information. Furthermore, accessibility is a hurdle, limiting the use of best practices in many policy support applications. In short, there is a user need for access to consistent, up-to-date source apportionment information.

Source apportionment service

The operational service fully exploits the regional CTM LOTOS EUROS forced by TNO emission information and CAMS data products to track the contributions of predefined source categories. The current version of this service focuses on European cities. The prototype service is a demonstrator and will be developed further to meet user requirements.

The sector source allocation product allows focus on various sectors of trade and activities in Europe and provides insight in their contributions to air pollutant concentrations. The source sector allocation product allows a differentiation between local and non-local contributions. The local contribution is defined as the mass contribution from a given sector originating from PM and precursor emissions from the grid cell in which the point of interest is located.
   Overview of sectors.

The country source allocation product quantifies the transboundary contribution to modelled air pollution episodes and identifies the most important contributing countries.
   Overview of countries.

Daily production

The information flow is illustrated in the figure blow. Note that the definition of the labels is in principle flexible, which allows customized studies to be performed.

Every day, the source apportionment simulation is extended with the previous day. The LOTOS-EUROS simulation is driven by ECMWF meteorology, TNO emission information, as well as time resolved information for boundary conditions and fire emissions from CAMS. Tailoring the service to a particular region is possible by including regional specific emission information for the region of interest. Local activity patterns can be used to prescribe the emission variability. Where possible temporal variable emissions are calculated based on meteorological data, such as domestic heating emissions based on heating degree days. Evaluation of the modelled results is performed periodically, using in-situ data.

In the near future the resolution of the model simulation in this demonstrator will be increased.