more serious in the Middle- East. This phenomenon causes a lot of environmental and socio- economic problems in Iran and several other Middle-Eastern countries. A Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used for trajectory analysis in order to reconstruct the origins of air masses in dust storms over several cities in the Western Parts of Iran. Backward trajectories analysis by HYSPLIT model showed that the main source of two occurrences of dust storms over several Iranian western cities has been originated from Syria passing through Iraq and arriving at the Western part of Iran. The Moderate Resolution Imaging Spectroradiometer (MODIS) images was used to monitor the monthly vegetation changes in the dust storm source areas. The Enhanced Vegetation Index (EVI) was obtained from recent MODIS vegetation data (2002-2009). Results revealed that source areas anthropogenic activities that reduced vegetation cover and activated wind erosion caused EVI numerical value reduction and dust storms
