Water vapour in the air can be extracted by condensation - cooling the air below its dew point, exposing the air to desiccants, or pressurizing the air. Unlike a dehumidifier, an ATMOSPHERIC WATER GENERATOR(AWG) is designed to render the water potable. AWGs are useful where pure drinking water is difficult or impossible to obtain, because there is almost always a small amount of water in the air that can be extracted. The two primary techniques in use are cooling and desiccants. Many atmospheric water generators operate in a manner very similar to that of a dehumidifier: air is moved over a cooled coil, causing water to condense. The rate of water production depends on the ambient temperature, humidity, the volume of air passing over the coil, and the machine's capacity to cool the coil. These systems shrinkage air temperature, which in turn reduces the air's capacity to carry water vapour.