Fraction of secondary formed particulate matter on total mass in October 2006: The particulate matter observed in the atmosphere is directly emitted or secondarily formed from gaseous precursors. This so-called secondary fraction can strongly vary in time and depends on the local conditions. Source: Ralf Wolke/TROPOS
Modeling of regional and urban air quality
For the description of complex atmospheric processes, three-dimensional model systems of varying complexity are developed, tested and applied on different scales. With these models as toolbox scientific as well as legal tasks regarding air quality are addressed. Models are indispensable tools in the search for efficient and cost-effective possibilities of compliance of relevant limit values for the protection of human health for gaseous and particulate air pollutions defined or suggested in directives by the European Commission. Such simulations are conducted with the complex three-dimensional modeling system COSMO-MUSCAT that has been developed at TROPOS. The model system was successfully tested in international model intercomparison studies and was applied for air quality studies. In several projects the dynamics of primary and secondary particles was simulated and their feedback on the radiative budget was investigated. An example of this kind of activity is the investigation of the formation of secondary aerosol particles in regions with high ammonia emissions, caused from agriculture and livestock husbandry. Furthermore, the multiscale model ASAM (also developed at TROPOS) was used for microscale simulations in building complexes with concern to particle measurements close to traffic.