A humidifier is a machine you put in a room to add water to the air, so the air is less dry. People use one in winter, in rooms with air-conditioning, or when dry air hurts the throat or skin. You fill a tank with water; the machine turns it into a fine mist. The opposite machine, a dehumidifier, takes water out of the air. In Taiwan both are common household things, and shops often sell them side by side. Though actually, too much mist is not better — a room that is too wet can grow mould, so you use a humidifier when the air is dry, not all year.

加濕器