Environmental factors influencing the deterioration of Nikka Stone used in Koshien Hall were investigated through field surveys of current conditions. The main results obtained were as follows: 1. Deterioration of Nikka Stone used in Koshien Hall was classified into three categories: algal contamination, detachment, and salt efflorescence. 2. There are several possible causes of detachment, including freezing/thawing cycles caused by high stone-water content and high concentration of evaporation from the surface of water from the surroundings, salt efflorescence, and so on. 3. Small quantities of rainfall and sunshine can contribute to algal growth
