Energy, Environment and Water Research Center

Energy, Environment and Water Research Center

Abstract: The production, transformation and transport processes of atmospheric pollutants in the Greater Mediterranean Region are the main objectives of the current presentation. The Greater Mediterranean Region is a key-sensitive area due to the unique climatic and air quality characteristics associated with the regional climatic patterns, the geomorphology (land and water contrast) and the coexistence of pollutants from different origin. The Mediterranean Region including the Sahara desert and important part of Europe is often influenced by high levels of desert dust, long-range transport of pollutants from Europe and intense photochemical activity, leading to atmospheric pollutant concentrations higher than the imposed EU limit values. The processes occurring along the characteristic paths of transport, the production of various generations of pollutants and the role of mineral dust and sea-salt are under consideration in this study. The modeling tools have been revised accordingly by the development and improvement of several physico-chemical mechanisms. In particular, the new development has included the impacts of desert dust on photochemical processes, the sea salt particle production and the treatment of soil dust particles as reactive agents (through the incorporation of heterogeneous chemical processes). Sensitivity tests have been carried out for each part of the development. The conclusions derived from the tests supported the fact that high concentrations of desert dust particles in the atmosphere can reduce the photolysis rates and cause reduction of ozone and sulfate concentration (5% and 10% of the concentration without the dust influence, respectively). The implementation of sea salt particle production in the chemical transport model has shown reasonable agreement with the observations and enriched the coarse anthropogenic sulfate concentration with the sea salt sulfate fraction. Finally, the implementation of the heterogeneous reactions on dust particles has revealed changes in the gaseous and particulate pollutant concentrations that, in several cases, enhanced the model performance. Combining this information with the capability of each species to affect solar radiation (absorption, scatter, extinction) and taking into account their deposition pathways, interesting insights can emerge on the potential climatic and environmental impacts for the Greater Mediterranean Region.