EN
Rapid technical progress in the past several decades brought about a new threat for stone monuments caused by pollution of the atmosphere, soil and water. Harmful substances favour the appearance on stone surfaces of stratifications which are difficult to remove and which hamper the natural exchange of gases and steam in the porous stone. Another form of the harmful influence of pollution is the chemical reaction of acids, which are present in the contaminated atmosphere, with certain components of the stone. An effective protection of monuments against those threats depends on early conservation before the object is devastated. Otherwise, far-reaching intervention and considerable financial means become indispensable. Prophylaxis in conservation should consist of the detection and removal of changes which are still harmless. The task of the conservation services should include a proper organization of periodical checks and examinations of stone objects as well as the removal of the damage during the course of its appearance