International audienceA k-means cluster analysis of 96 hour trajectories arriving in Southeast (SE) Spain at 3000, 1500 and 500 m for the 7-year period 2000?2006 has been performed to identify and describe the main flows arriving at the study area. The dependence of the aerosol size distribution on the air mass origin has been studied by using non-parametric statistics. There are statistically significant differences on aerosol size distribution and meteorological variables at surface level according to the identified clusters