One of the factors/examples that can negatively affect online reviews from users of vacation rentals is the smell of mold during their stay. Since vacation homes are often located in humid areas, mold problems are often caused by a small amount of mold, which can make users feel uncomfortable. If the smell of mold is too strong, it may cause users to feel sick. Especially during long rainy seasons, typhoons, or when there are few users of the vacation home, it is necessary to take proper measures against mold.