Research topic

Research Topic

One of the major concerns today in Europe is air quality in urban areas. In a majority of large cities, the number of days with pollutant concentrations above critical values increases constantly over years. This has an important impact on the quality of the environment, that has also a cost in terms of public health and economic activity.
It appears from the last years that predicting pollution episodes is not sufficient. There is now a necessity to prevent pollution episodes from occurring. To reach this objective, governmental authorities have two types of actions:

First they control the pollutant emissions levels from industrial systems (chemical industry, furnaces, cars,...). This implies substantial research and development efforts from the industry to stay below the maximum authorized levels. Numerical simulation tools are of great help in the design phase of the system, because they are able to predict emissions.

Second, to reduce the contribution of cars to the emissions, governments restrict the traffic, either permanently or during alerts only. However, the strong non-linearity of chemistry, reenforced by the coupling with the atmospheric dynamics and radiation, makes it very difficult to define a strategy that will guarantee a reduction of pollutant levels. Recent studies have shown for example that reducing traffic in the morning has a positive impact on pollution, but reducing traffic in the afternoon has a negative impact! Also, whether the impact is negative or positive depends on whether the measurements are made in the city or downwind. In this context, urban atmospheric simulations have a crucial role to play. They provide a quantitative and reliable estimation of the impact of any change in pollutant emissions, taking into account the local weather conditions and the local orography.

The aim of this network is to bring together some of the best groups in Europe in the field of the simulation of reactive flows and especially to establish communication between scientists involved in pollution prediction in engines and furnaces and those involved in the dissemination of pollutants in the atmosphere. Exchanges between both communities will enhance the improvement of numerical tools, in terms of modelling but also in terms of complementarity. Such exchanges are extremely rare at the moment because the corresponding communities (industrial combustion systems on one side and atmosphere on the other side) have very few contacts. This project aims at creating such interactions.