In this programme, a wide range of research efforts are made that tend to characterise aspects of atmospheric dynamics which are more specific and relevant for the Western Mediterranean, and relate mostly to: extreme meteorological events that lead to risk situations (flash floods, cold spells, heat waves, or dangerous conditions for forest fires); processes to which pollutants are submitted from when they are emitted to the atmosphere, which severely condition their impact on the natural environment, human health and plant communities (recirculation processes, stratifications and development of boundary layers, formation of secondary compounds and chemical transformations in general, and special attention is paid to those that are photochemical in nature).