SAND AND DUST STORM: what and where?
Sand and dust storms, also called SDSs, are a natural phenomenon caused by atmospheric factors which have important impacts on the environment, societies’ economy and health (Akhlaq et al., 2012; Wang et al., 2011).
These phenomena are typical in the northern part of China and America, in the Middle East and in Australia, and usually happen in spring, winter and the first month of summer (Akhlaq et al., 2012). Sand and dust storms happen when there are strong gusts of wind which raise sand from an arid surface. The sand particles, by vibrating and moving with wind, break others particles into smaller ones, untill the small particles are able to stay suspended in the air and move with the wind (An et al., 2018). With time, the concentration of particles having a diameter smaller than 10mm increases, and it can have consequences in the quality of the air and on the human respiratory system (An et al., 2018). As shown by figure 2, the SDS happen more frequently in the North Hemisphere, from North Africa to the Middle East to China. The desserts which cause the most SDS in the World are the Sahara and the Sahel in North Africa. Those areas are the source of 65% of the global total dust emissions (Wang et al., 2011).
SDSs are a risk for the economy, the environment and health because the small size of the particles can create pollution, as well as health and ecological problems. They can create a low-visibility situation, and it can be a problem for aviation and transports. The economic consequences are caused mostly from the strong wind, which can destroy constructions and cause desertification (Akhlaq et al., 2012). Dust storm can affect also dust storm, by the moment that the sand particles in the air affect the scattering and absorption, acting like a real cloud and change the cloud cover (An et al., 2018). On the other hand, sand and dust storms also have positive consequences: mineral and desert dust are an important source of nutrients in the ocean and also transport alkaline particles which help reduce rain acidity (Wang et al., 2011).
The cost caused by SDS events are not well known: the bigger costs are caused by a cumulative consequence on the society, from the cost to fix the social problems caused (like economy, health, …) (Middleton et al., 2019). A possible solution to this phenomenon is to convert the bare ground soil, maybe used for farming, to forest soil: if the vegetation increases, the wind’s speed and power cannot augment, and the damage of SDS will decrease (Middleton et al., 2019). Unfortunately, this kind of solution can change the economy and the resources of a country; it is thus impossible.
Figure 2: Global distribution of Sand and Dust storm (source: Wang et al., 2011)
