A cabin air control system comprising: an upper housing including a first end and an opposite second end; a lower housing including: a first end; an opposite second end; an air inlet passage with an inlet opening at the first end of the lower housing; and a regeneration air chamber communicating with the air inlet passage via a regeneration air port, wherein the upper housing and the lower housing together define an adsorption unit chamber above the regeneration air chamber and communicating with the air inlet passage via an adsorption air port, and the upper housing further includes an outlet passage, an outlet opening and an exhaust conduit, the outlet passage selectively communicating with the outlet opening and the exhaust conduit; a single adsorption unit disposed in the adsorption unit chamber, the adsorption unit being configured to adsorb moisture and/or carbon dioxide; a heater disposed in the regeneration air chamber, the heater being configured to heat air before being delivered to the adsorption unit, and the heated air being used to regenerate the adsorption unit; and a flap control assembly configured to switch between an adsorption mode and a regeneration mode, the flap control assembly including an inlet flap configured to be rotated between a first inlet position corresponding to the adsorption mode and a second inlet position corresponding to the regeneration mode, wherein, in the first inlet position, the adsorption air port is open and the regeneration air port is closed by the inlet flap, so that the air flows into the adsorption unit chamber and bypasses the heater, and in the second inlet position, the adsorption air port is closed by the inlet flap and the regeneration air port is open, so that the air flows into the regeneration air chamber, through the heater and into the adsorption unit chamber, and is heated to regenerate the adsorption unit. an upper housing including a first end and an opposite second end; a lower housing including: a first end; an opposite second end; an air inlet passage with an inlet opening at the first end of the lower housing; and a regeneration air chamber communicating with the air inlet passage via a regeneration air port, a first end; an opposite second end; an air inlet passage with an inlet opening at the first end of the lower housing; and a regeneration air chamber communicating with the air inlet passage via a regeneration air port, wherein the upper housing and the lower housing together define an adsorption unit chamber above the regeneration air chamber and communicating with the air inlet passage via an adsorption air port, and the upper housing further includes an outlet passage, an outlet opening and an exhaust conduit, the outlet passage selectively communicating with the outlet opening and the exhaust conduit; a single adsorption unit disposed in the adsorption unit chamber, the adsorption unit being configured to adsorb moisture and/or carbon dioxide; a heater disposed in the regeneration air chamber, the heater being configured to heat air before being delivered to the adsorption unit, and the heated air being used to regenerate the adsorption unit; and a flap control assembly configured to switch between an adsorption mode and a regeneration mode, the flap control assembly including an inlet flap configured to be rotated between a first inlet position corresponding to the adsorption mode and a second inlet position corresponding to the regeneration mode, wherein, in the first inlet position, the adsorption air port is open and the regeneration air port is closed by the inlet flap, so that the air flows into the adsorption unit chamber and bypasses the heater, and in the second inlet position, the adsorption air port is closed by the inlet flap and the regeneration air port is open, so that the air flows into the regeneration air chamber, through the heater and into the adsorption unit chamber, and is heated to regenerate the adsorption unit.