Stonework is corroding through the world mostly due to pollution of the atmosphere. While the rate of corrosion on structurally used stone may be very slow, a centimetre a century, this rate on decorative stonework is disastrous. Priceless statues are being eaten away.
Sulphur dioxide formed by burning high-sulphur fossilized fuel is especially damaging to limestone. The calcium carbonate interacts with the sulphur dioxide and becomes calcium sulphate which is more soluble and washes away in the rain.