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Mineral dust is a term used to indicate atmospheric aerosols originated from the suspension of minerals constituting the soil, being composed of various oxides and carbonates. Human activities lead to 30% of the dust load in the atmosphere. The Sahara Desert is the major source of mineral dust, which subsequently spreads across the Mediterranean (where is the origin of rain dust) and Caribbean seas into northern South America, Central America, North America, and Europe. Additionally, it plays a significant role in the nutrient inflow to the Amazon rainforest. The Gobi Desert is another source of dust in the atmosphere, which affects eastern Asia and western North America. ==Characteristics== Mineral dust is mainly constituted of the oxides (SiO2, Al2O3, FeO, Fe2O3, CaO, and others) and carbonates (CaCO3, MgCO3) that constitute the Earth's crust. Global mineral dust emissions are estimated at 1000-5000 millions of tons per year, of which the largest part is attributed to deserts. Although this aerosol class is usually considered of natural origin, it is estimated that about a quarter of mineral dust emissions could be ascribed to human activities through desertification and land use changes. Large dust concentrations may cause problems to people having respiratory problems. Another effect of dust clouds is more colorful sunsets. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mineral dust」の詳細全文を読む スポンサード リンク
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