# Sand and Dust Storms: Impact Mitigation
## 3 The Scale of SDS Impacts: Countries Affected
Most of the assessments of global wind erosion sources do not feature political boundaries and, although long-distance transport is often traced from atmospheric monitoring stations via back-trajectory analysis to specific source areas, as far as we are aware, there has been no systematic attempt to assess the global distribution of SDS impacts by nation state. Figure 2 is the result of our endeavors in that direction. Using peer-reviewed published sources, we have allocated each individual party to the UNCCD (Note that there are 196 parties to the UNCCD as of the start of 2017, comprising 193 UN member states plus three others: the European Union, the Cook Islands, and Niue) to one of four categories: as a source area for SDS; as a deposition area for SDS due to long-range transport; as a country where soil erosion by wind occurs (but not on a sufficient scale to warrant inclusion in the first category); and as a country where no SDS activity or wind erosion has been recorded in peer-reviewed sources. The complete record of country parties by category is given, with supporting references, in Supplementary Material 1. This classification of countries according to the global distribution of SDS impacts is simple and involves some degree of expert judgment, as outlined below, but it certainly indicates the globally extensive nature of SDS issues. A total of 151 country parties (77% of all parties) are affected directly by SDS issues and 45 (23% of all parties) are classified as SDS source areas. Most of the countries classified as SDS source areas (38 of 45) are in Africa and Asia. The first three categories are not mutually exclusive, and many individual countries could be included in more than one category. For example, countries with SDS source areas also experience deposition of material from those sources and often also from sources elsewhere. Iran is an example, having a significant regional source in the Hamoun Basin [49] and receiving dust from several other Middle Eastern countries [50]. Some countries outside the drylands receive dust deposits only, after long distance transport of material from major sources, such as Japan which receives dust from Chinese and Mongolian deserts [51], and Panama which receives Saharan dust [52]. However, other countries receive desert dust while also experiencing some wind erosion on their own soils. Sweden is an  
Figure 2: Number of country parties affected by SDS. example here [28; 31]. In all these cases, a judgment call has been made regarding each country's most appropriate category. The USA, for instance, has been categorized as an SDS source area because it has both active sand dunes [53] and desert dust sources [54] within its territory, but the country also receives deposits of desert dust transported from sources in Mexico [55], Asia [56] and Africa [57], as well as experiencing wind erosion on its domestic agricultural soils [58]. At this point, we are not distinguishing between \"good\" and \"bad\" SDS activity. In the US case, for instance, the arrival of long-range dust from Asian sources has been investigated both for its supply of plant nutrients [59] and its adverse effects on air quality [60]. We suspect that the 77% of all parties affected directly by SDS issues is a conservative figure. This is because some of the countries where no SDS activity or wind erosion has been recorded in the peer-reviewed literature may be recipients of desert dust deposits but such deposits have simply not been catalogued or monitored. Such countries include Haiti, Liechtenstein, and Luxembourg, all of which are located in well-documented seasonal pathways of Saharan dust transport [61]. It is also worth noting that countries where no SDS activity or wind erosion has been recorded are not completely unaffected by SDS issues because all countries are impacted indirectly via the numerous effects SDS have on the Earth system.