A device for conditioning an air in an enclosed space, the device comprising: a first sorption unit, and a second sorption unit, wherein each of the first sorption unit and the second sorption unit comprises a receptacle for receiving a sorbent configured to sorb one or more air constituents of the air in the enclosed space, e.g., carbon dioxide and/or water, and wherein each of the first sorption unit and the second sorption unit is configured to: - be transferred from a sorption mode into a desorption mode; - be transferred from the desorption mode into the sorption mode; - in the sorption mode, sorb the one or more air constituents from air of the enclosed space; and - in the desorption mode, desorb the one or more air constituents; an air distribution device configured to, in an operating state (ONST), alternately operate one of the first sorption unit and the second sorption unit in the sorption mode, and operate the other one of the first sorption unit and the second sorption unit in the desorption mode, wherein the operating state (ONST) comprises a first operating state and a second operating state, and wherein the air distribution device is further configured to: - in the first operating state, switch to the second operating state in which exchange of the air of the enclosed space with exterior air is provided, if it is determined that a concentration of at least one air constituent of the one or more air constituents is above a corresponding pre-determined upper limit; - in the second operating state, switch to the first operating state, if it is determined that concentrations of two or more, e.g., all, air constituents of the one or more air constituents are within their corresponding pre-determined upper limit; - in the first operating state, switch to an idle state, in which none of the first sorption unit and the second sorption unit is in the sorption mode, if it is determined that the concentrations of all air constituents of the one or more air constituents are within their corresponding pre-determined upper limit minus hysteresis. a first sorption unit, and a second sorption unit, wherein each of the first sorption unit and the second sorption unit comprises a receptacle for receiving a sorbent configured to sorb one or more air constituents of the air in the enclosed space, e.g., carbon dioxide and/or water, and wherein each of the first sorption unit and the second sorption unit is configured to: - be transferred from a sorption mode into a desorption mode; - be transferred from the desorption mode into the sorption mode; - in the sorption mode, sorb the one or more air constituents from air of the enclosed space; and - in the desorption mode, desorb the one or more air constituents; - be transferred from a sorption mode into a desorption mode; - be transferred from the desorption mode into the sorption mode; - in the sorption mode, sorb the one or more air constituents from air of the enclosed space; and - in the desorption mode, desorb the one or more air constituents; an air distribution device configured to, in an operating state (ONST), alternately operate one of the first sorption unit and the second sorption unit in the sorption mode, and operate the other one of the first sorption unit and the second sorption unit in the desorption mode, wherein the operating state (ONST) comprises a first operating state and a second operating state, and - in the first operating state, switch to the second operating state in which exchange of the air of the enclosed space with exterior air is provided, if it is determined that a concentration of at least one air constituent of the one or more air constituents is above a corresponding pre-determined upper limit; - in the second operating state, switch to the first operating state, if it is determined that concentrations of two or more, e.g., all, air constituents of the one or more air constituents are within their corresponding pre-determined upper limit; - in the first operating state, switch to an idle state, in which none of the first sorption unit and the second sorption unit is in the sorption mode, if it is determined that the concentrations of all air constituents of the one or more air constituents are within their corresponding pre-determined upper limit minus hysteresis.