Why Does Acid Rain Cause Damage To Marble Statues

In exposed areas of buildings and statues we see roughened surfaces removal of material and loss of carved details.

Why does acid rain cause damage to marble statues.

Many sculptures throughout the united states and europe are carved from marble or limestone. The acids in acid rains can react with caco by producing soluble salts. Acid deposition can be caused by natural sources such as volcanoes but it is mainly caused by the release of sulfur dioxide and nitrogen oxide during fossil fuel combustion when these gases are discharged into the atmosphere they react with the water oxygen and other gases already present there to form sulfuric acid ammonium nitrate and nitric acid. Acid rain can ruin buildings and statues by stripping away the material and corroding metal that makes up these structures.

When sulfurous sulfuric and nitric acids in polluted air and rain react with the calcite in marble and limestone the calcite dissolves. When sulfuric acid rain strikes these statues the reaction of the sulfuric acid with the calcium carbonate yields calcium sulfate and carbonic acid. A lot of buildings and statues are made of basic alkaline materials such as limestone. The carbonic acid further breaks down into water and carbon dioxide.

When an acid comes into contact with these materials it causes an exothermic reaction the dissolves the. Stone surface material may be lost all over or only in spots that are more reactive. What causes acid rain. That s why acid rain dissolves statues made of marble.

Architects chose limestone marble steel and brass as durable materials intended to resist the elements. And nitric acids in polluted air react with the calcite in marble and limestone the calcite dissolves.