US Patent 11490628 Air composition adjusting device

An air composition adjusting device includes: a carbon dioxide separator that separates carbon dioxide from air-to-be-treated to be supplied to a target space; a gas supply path including a high concentration gas supply path through which the carbon dioxide separator communicates with the target space; and a controller that performs a carbon dioxide concentration raising operation of supplying a high carbon dioxide concentration gas, which has a higher carbon dioxide concentration than air-to-be-treated before being treated, to the target space through the high concentration gas supply path.