A dust storm or sandstorm is a meteorological phenomenon common in arid and semi-arid
regions and arises when a gust front passes or when the wind force exceeds the threshold
value where loose sand and dust are removed from the dry surface. Particles are transported
by saltation and suspension, causing soil erosion from one place and deposition in another.
The Sahara and drylands around the Arabian peninsula are the main source of airborne dust,
with some contributions from Iran, Pakistan and India into the Arabian Sea, and China's storms
deposit dust in the Pacific. It has been argued that recently, poor management of the Earth's
drylands, such as neglecting the fallow system, are increasing dust storms from desert margins
and changing both the local and global climate, and also impacting local economies. 

The term sandstorm is used most often in the context of desert sandstorms, especially in the
Sahara, when, in addition to fine particles obscuring visibility, a considerable amount of larger
sand particles are blown closer to the surface. The term dust storm is more likely to be used
when finer particles are blown long distances, especially when the dust storm affects urban
areas.