Influence of Transport Phenomena on Pollutants Concentration in Mediterranean Tunisian Regions

The objective of this study is to investigate the origin of the polluted air masses in the Tunisian Mediterranean regions and to characterize the atmospheric conditions and the transport and dispersion mechanisms that give rise to pollution events. For this end, we conducted continuous measurements campaigns of surface ozone concentration and meteorological parameters during summer 2011 using mobile and fixed stations in the Tunisian regions. The results indicated that the seasonal variability of ozone concentrations was related to European and Saharan transport events. Long range transport of pollutants from Europe resulted in O₃ loading and frequent surpassing of the European standard limits in the Mediterranean Tunisian sites. During these events, the weather conditions support photochemical phenomena. The Saharan events provided the importance of chemical reactions and radiative impact involving dust particles which may reduce the photochemical production of ozone.