A city skyline very blurred by smog.

Atmospheric dispersion

Atmospheric dispersion models are used to estimate or to predict the downwind concentration of air pollutants or harmful substances emitted from sources. They have widespread use in situations such as emergency response, the planning of policies and strategies relating to air quality and hazards, and estimating the impact of the construction of specialised facilities. These models can simulate the dispersion and chemical reaction of volatile compounds. They account for the effect of meteorology in the transport, dispersion and deposition of these compounds, and for how they are transformed as a result of radioactive decay, chemical transformation, interaction with the surface and ecosystems, etc.
The JRC has developed ENSEMBLE, a web-based platform that is used to compare and evaluate scientific models that have been set up to study the transport and dispersion of chemical substances in the atmosphere. The system was originally developed for nuclear emergencies but is now used for all kinds of atmospheric models, using monitoring data, in situ air quality data, radiological and meteorological data, vertical profiles and remotely sensed data. The ENSEMBLE system also allows users to perform on-line ensemble analysis and independent model evaluation and intercomparison. It has been used for the analyses of many different atmospheric dispersion cases (release of radioactive substances, volcano eruptions, dispersion from accidental fires, air quality at different scales, etc.) by modelling communities throughout the world.

The JRC also supports the Air Quality Modelling Evaluation International Initiative (AQMEII) which aims to promote research on regional air quality model evaluation in Europe and North America through the exchange of information on practices, the realisation of inter-community activities and the identification of research priorities, keeping a focus on policy needs. AQMEII is an initiative coordinated by the JRC and the US Environmental Protection Agency, and is one of the communities that uses ENSEMBLE.


Further information