The corrosion of materials exposed to the atmosphere is most commonly due to chloridization and sulphidization of iron and its alloys, the chloridization of aluminium, the sulphidization of copper and its alloys, and the sulphidization of marble and masonry. The exact processes remain obscure, despite research, although the presence of water assists vigorous corrosive action.
In the USA in 1975, it is estimated that the costs associated with such corrosion amounted to over $70 billion per year.
Atmospheric corrosion is in many locations due to natural processes.