Arid and semi-arid areas cover a big part of the earth’s surface. They are mostly located around the tropics about
23° north and south of the equator (Fig. 2). According to the commonly used Köppen-Geiger climate classification
these areas are defined by limited precipitation and high potential evaporation rates. The climatic conditions
especially of the hot deserts seem to supply the best requirements for the effective use of solar power. High rates of
solar irradiation throughout the year promise huge energy outputs (Fig. 3). But high amounts of available mineral
dust and frequent dust events induce heavy soiling and therefore the advantages of this area could be reduced
considerably. Special coatings, designed to reduce the accumulation of dust on the glazing, have to be adapted to
these particular conditions. Beyond the economic view, the necessary cleaning process consumes serious amounts of
water. Considering the deficit of this resource in arid regions, soiling potentially reduces the sustainability of solar
power usage. Therefore, a better understanding of the complex soiling process in deserts and, as a result, a dust risk
map is needed.