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 100-500 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 30% of the mineral dust load in the atmosphere could be ascribed to human activities through desertification and land misuse.
Large dust concentrations may cause problems to people having respiratory problems. Another effect of dust clouds is more colorful sunsets.
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