Anyway got off topic it is the acid in the rain reacting with the marble and producing gas possibly other stuff as well as i said can t remember thus it looks as though the marble is changing physically i m sure a google search of the make up of marble and acid rain and the possible reactions of the molecules will give you your answer.
Acid rain weathering a marble statue.
Old statues monuments and tombstones are vulnerable to acid rain because they were made of limestone.
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.
Buildings and statues made from rock are damaged as a result.
Acid rain is a rain or any other form of precipitation that is unusually acidic meaning that it has elevated levels of hydrogen ions low ph it can have harmful effects on plants aquatic animals and infrastructure.
James williams takes a tour.
This is worse when the rock is limestone.
Acid rain harms fish and trees but it also makes chemical weathering happen more quickly.
In exposed areas of buildings and statues we see roughened surfaces removal of material and loss of carved details.
In exposed areas of buildings and statues we see roughened.
When sulfurous sulfuric and nitric acids in polluted air react with the calcite in marble and limestone the calcite dissolves.
Acid precipitation affects stone primarily in two ways.
Marble like all calcareous rocks is particularly sensitive to degradation by acid chemicals and to weathering.
On metal patina is a coating of various chemical compounds such as oxides carbonates sulfides or sulfates formed on the surface during exposure to atmospheric elements oxygen rain acid rain carbon dioxide sulfur bearing compounds a common example of which is rust which forms on iron or steel when exposed to oxygen or more specifically the surface that develops on weathering.
When sulfurous sulfuric and nitric acids in polluted air and rain react with the calcite in marble and limestone the calcite dissolves.
Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide which react with the water molecules in the atmosphere to produce acids.
Stone surface material may be lost all over or only in spots that are more reactive.
Acid rain damage can be seen on many of the monuments in washington d c.
Over decades of exposure to acid rain the details of a statue can be lost slowly turning them into featureless blobs.
