Regarding environmental condition, cases of substances being brought by outsiders resulting in exposure are increasing, and the case of the deteriorated wall painting of Takamatsuzuka Kofun is a known example.
環境の影響という面でも高松塚古墳壁画劣化の例に顕著なように、外部者が持ち込んだ物が汚染を招くという事態が多くなっている。