The Sahara desert is the largest hot desert in the world. It spans over 9 million square kilometers, the same size as the United States or China, from the Mediterranean sea to the Niger River valley. The Sahara is also the largest source of eolian dust in the world. Saharan dust is mainly produced by wind storms in the desert. Human impacts of Saharan dust can include respiratory difficulties and other adverse health conditions during dust storms in the surrounding regions. However eolian dust from the Sahara can travel up to the Amazon basin where it bring mineral nutrients such as phosphorus, promoting soil development on land.