Damage to cultural artefacts by environmental pollution

Acid rain produced by oxides of nitrogen and sulphur from oil refineries and tourist buses on the Yukatan peninsula is destroying the temples, murals and megaliths of ancient Mayan civilization. The acid rain eats into the stone surface at once, corroding crevices, ledges and moulding. The cost of maintaining Germany's historic buildings against pollution-accelerated erosion is about $100 million a year.