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 ope rating at present on the north coast is performed using a meso-beta nu merical model, paying particular attention to the diffusive physical m echanisms. The study is applied to the conditions of sea-land breeze d evelopment. 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-l evel concentration higher than 5 mu g/m(3) are restricted over a limit ed and mountainous region during the whole diurnal cycle. However, whe n 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 chang es in the spatial and temporal evolution of the ground-level concentra tion.