Why Does Acid Rain Erode Marble

Stone such as granite and gneiss release toxic aluminum ions into the environment when exposed to acid rain.

Why does acid rain erode marble.

Acid rain s ability to dissolve marble and limestone makes it hazardous to buildings and outdoor monuments. When sulfurous sulfuric and nitric acids in polluted air and rain react with the calcite in marble and limestone the calcite dissolves. These constituents may occur naturally from processes such as volcanic eruptions and the oxidation of rocks or their presence in. Sulfur dioxide plus water makes sulfurous acid.

Acid rain effects on buildings. Erosion due to dissolution. Acid rain contains carbonic nitric and sulfuric acid that are produced by oxidation and dissolution in water of gaseous oxides co 2 no 2 and so 2 present in the air as chemical pollutants. When sulfurous sulfuric and nitric acids in polluted air react with the calcite in marble and limestone the calcite dissolves.

Marble like all calcareous rocks is particularly sensitive to degradation by acid chemicals and to weathering. Acid rain is a byproduct of both natural and man made conditions. How does acid precipitation affect marble and limestone buildings. Marble is mainly calcium carbonate.

The precursors or chemical forerunners of acid rain formation result from both natural sources such as volcanoes and decaying vegetation and man made sources primarily emissions of sulfur dioxide so 2 and nitrogen oxides no x resulting from fossil. Field investigations of acidic deposition effects on limestone and marble. Acidic precipitation can be caused by natural volcanoes and man made activities such as from cars and in the generation of electricity. Acid rain is composed of sulfuric acid h2so4 or nitric acid hno3 formed as secondary pollutants from so2 other sulfur oxides and nitrogen monoxide no.

But if you add an acid you add hydrogen ions h which will react with the carbonate to form hydrogen carbonate hco3 ions which are very soluble in water and the limestone will dissolve. Limestone is mostly made up of the mineral calcium carbonate caco3. It is well established that either wet or dry deposition of sulfur dioxide significantly increases the rate of corrosion on limestone sandstone and marble. In exposed areas of buildings and statues we see roughened surfaces removal of material and loss of carved details.

During the past several years research in the effects of acidic deposition on carbonate stone has been conducted under the national acid precipitation assessment program napap 2 to define the incremental effect of acidic deposition under ambient environmental conditions. Acid precipitation affects stone primarily in two ways. This is not very soluble so rocks don t dissolve very quickly. Or if there is more acid two hydrogen ions will.

Igneous and metamorphic rocks exposed to acid rain can poison ecosystems. Stone surface material may be lost all over or only in spots that are more reactive.