A numerical study of the transport and diffusion of coastal pollutants during the breeze cycle in the Island of Mallorca

An Eulerian study of the distribution over the Island of Mallorca of a non-reactive pollutant (SO2) emitted from an electric power plant operating at present on the north coast is performed using a meso-beta numerical model, paying particular attention to the diffusive physical mechanisms. The study is applied to the conditions of sea-land breeze development. This is a local circulation that dominates the flow during the summer and favours transporting pollutants from the coast toward the centre of the island. Results indicate that values of the ground-level concentration higher than 5 mu g/m(3) are restricted over a limited and mountainous region during the whole diurnal cycle. However, when the simulation is carried out with the inclusion of a twin electric plant which may be built on the south coast, the affected area becomes larger, especially early in the morning, when air over the island is sinking as a consequence of the land breeze development. The inclusion of dry deposition in the simulations does not produce important changes in the spatial and temporal evolution of the ground-level concentration.