Abstract: An apparatus for humidification and pressure control of gas. The apparatus may include a container for holding an aqueous liquid, a first tube for receiving gas from a gas source and being arranged to pass the gas into the liquid through an opening at a lower end of the tube, and a second tube for discharging the gas from an upper portion. The second tube may surround the first tube and may include an opening at its lower end that is below the lower end of the first tube.