Inorganic deterioration affecting the Altamira Cave, N Spain: quantitative approach to wall-corrosion (solutional etching) processes induced by visitors.

In order to study the wall corrosion processes induced by visitors in the Altamira Cave (northern Spain), a multidisciplinary study was conducted in the cave. For a period of 1 year, a microclimate monitoring system, measuring the temperature, relative humidity, CO2 and 222Rn concentrations was operated. Host rock samples were collected as well as indoor and outdoor atmospheric particulate matter. These data are used for a quantitative assessment of the wall corrosion processes. The presence of visitors was found to enhance the corrosion processes up to 78 times in comparison with the natural processes. Outdoor air pollution did not have a significant affect.