Environmental pollution caused by acidic gases such as carbon dioxide, flon and other toxic gases from industry has been a major social problem, and its effect on cultural property has been anticipated. Among these components, acidic gases such as nitrogen dioxide and sulfur dioxide, acidic mist such as chloric, nitric, and sulfuric ions in the air can be mentioned as representative causes of serious problems for cultural property. It is very important to know the change of concentration of such acidic gases and mists in the environment of exhibition and conservation facilities of cultural properties, in order to inquire the best condition for conservation. In this study, these ions, Cl^-, NO 3^-</sup >and SO 4^2-, were measured in the surroundings of cultural property and their behavior was checked based on the result of measurement. Samples were collected from thirteen control sites of various conditions such as inside and outside museums, galleries and conservation facilities. For the collection of NO 2 and SO 2, a passive sampler was used; for that of Cl^-, NO 3^-</sup >and SO 4^2-, a gauze cloth method was used. Ion chromatography was used to measure the concentration of these ions. The results were recorded as monthly average. Based on these data, the effects of acidic ions in the air outside and inside conservation facilities were studied. Test pieces of such metals as Cu and Ag were exposed at the same sampling sites. These test pieces were collected every three months and the changes of their surface color were measured by colorimetry. The relationship between the difference of colors and concentration of gas and mist were checked and discussed.