# Sand and Dust Storms: Impact Mitigation
## 1 Introduction  
Sand dust storms (SDS) are atmospheric events created when small particles are blown from land surfaces. SDS occur when strong, turbulent winds flow over dry, unconsolidated, fine-grained surface materials where vegetation cover is sparse and sometimes altogether absent. These conditions are most commonly found in the world's drylands--deserts and semi-deserts--and hence this is where SDS are most frequent. Sand storms occur within the first few meters above the ground surface, but finer dust particles can be lifted much higher into the troposphere, where strong winds frequently transport them over great distances.  
SDS play an integral role in the Earth system, with impacts that are numerous and wide-ranging [1, 2]. These include effects on air chemistry and climate processes, soil characteristics and water quality, nutrient dynamics and biogeochemical cycling in both oceanic and terrestrial environments. All of these impacts have repercussions for human society, but people are also influenced more directly by a range of SDS hazards [3]. SDS can result in damage to crops and the removal of fertile topsoil, adversely affecting food production. Atmospheric dust can cause and/or aggravate a number of human health problems, including respiratory ailments and cardiovascular disease. Poor visibility can result in road traffic accidents. Other common forms of economic disruption include closure of transport services and cleaning of roads, houses and business premises.  
These hazards are of considerable importance for the residents of drylands but their significance is further magnified because desert dust events frequently involve long-range transport over thousands of kilometers, often taking fine particles far beyond dryland environments. These environmental and socio-economic impacts, which are frequently transboundary in effect, occur at local to global levels.  
We know that SDS vary in frequency and intensity seasonally, because of droughs, and over longer timescales [4; 5; 6]. Attempts to combat wind erosion with soil conservation measures have succeeded in reducing SDS in certain parts of the world (e.g., [7; 8]) but in other areas there has been a recent marked increase in wind erosion and associated dust storms. These areas include parts of the Arabian Peninsula [9; 10], the eastern Mediterranean [11; 12], Lower Mesopotamia and adjacent regions [13], and parts of northeast Asia [14]. In some cases, the frequency and intensity of SDS have increased as a result of human activities, including soil surface disturbance, desertification and land degradation.  
Given that SDS threats to livelihoods, environment and economy are likely to undermine the implementation of a broad range of the Sustainable Development Goal (SDG) targets, the United Nations General Assembly (UNGA) adopted resolutions entitled \"Combatting sand and dust storms\" in 2015 (A/RES/70/195) and 2016 (A/RES/71/219). These resolutions acknowledge that SDS represent a severe impediment to the sustainable development of affected developing countries and the well-being of their peoples and urge individual countries to address the challenges of SDS through relevant policy measures. The United Nations Convention to Combat Desertification (UNCCD) is playing a leading role in addressing SDS issues and helping countries to develop policy with a major focus on disaster risk reduction, as advocated by the Sendai Framework [15].  
Mitigating the impacts of SDS is a central theme of such policy measures and the purpose of this paper is to review the range of actions available to mitigate the numerous impacts of SDS, to highlight areas of uncertainty and to consider some of the research priorities for the future.