Why can the target humidity of the Xiaomi Smart Evaporative Humidifier in the Mi Home/Xiaomi Home APP only be set from 40% to 70%?

Question

Accepted Answer

The human body feels comfortable when the humidity is at 40% to 60%RH. When the ambient humidity is lower than 30%, the indoor humidity is dry, which can cause dry skin, sore throat, dry respiratory tract, and easily cause respiratory diseases such as asthma. When the ambient humidity is higher than 70%, the air will be very humid, bacteria can easily grow, and you will feel the sticky and uncomfortable feeling of touching the surrounding objects. Therefore, to make you feel comfortable and protect your health, the target humidity can be set from 40% to 70%.