----- The causes include the inflow of outside air during loading and unloading, increased humidity during rainfall, the presence of humidity sources (such as water areas, tanks, or equipment that generates steam), and condensation caused by moving items from low-temperature to high-temperature rooms. Depending on the location and layout of the room, its airtightness, and the presence or absence of air conditioning measures, humidity can fluctuate by more than 10% even during the same season. If issues arise in specific manufacturing areas or temporary storage spaces within a factory, enclosing the target area with a vinyl booth and controlling humidity with a dehumidifier can be considered as a countermeasure.

----- The appropriate relative humidity range for storing precision equipment (such as precision measuring instruments, analyzers, communication devices, scientific instruments, machine tools, optical equipment, etc.) is said to be 40-50%. Above 50%, corrosion and rust on precision equipment and condensation on sensors can cause accuracy deviations. Conversely, humidity below 40% can lead to static electricity, potentially causing electronic circuit failures. Proper humidity control and monitoring are essential to prevent equipment failures and defects.

----- Cardboard boxes show the highest strength when their moisture content is 8-9%. However, when the relative humidity exceeds 80%, the moisture content exceeds 15%, and the strength deteriorates to less than half. (Special attention is needed when storing stacked boxes.) Additionally, the humidity inside the boxes increases, which can affect the contents.

-----generally, at a room temperature of 29°C and a relative humidity of 75%, the discomfort index exceeds 80, causing many people to feel uncomfortable. Even at the same temperature, reducing the humidity to below 60% can significantly improve comfort.