A method of removing and capturing concentrated carbon dioxide from carbon dioxide laden air, the method comprising admixing a first flow of carbon dioxide-laden ambient air with not more than 50% by volume of an effluent gas, where the effluent gas is derived from a flue gas from the combustion of hydrocarbons, and directing the first flow of admixed ambient air to a first carbon dioxide removal structure; the first carbon dioxide removal structure comprising a sorbent supported upon a porous substrate and capable of releasably binding carbon dioxide to remove a predetermined portion of the carbon dioxide from the first admixed ambient air mixture; passing the first carbon dioxide removal structure into a first sealable carbon dioxide capture chamber, exhausting air from the first sealed capture chamber to reduce the air pressure therein, and passing steam, at a temperature of not greater than 120°C into and through the first carbon dioxide removal structure to strip carbon dioxide from the sorbent and regenerate the sorbent, and removing the stripped carbon dioxide from the first sealed capture chamber, so as to capture concentrated carbon dioxide; admixing a second flow of carbon dioxide-laden ambient air with not more than 50% by volume of an effluent gas, where the effluent gas is derived from a flue gas from the combustion of hydrocarbons, and directing the flow of admixed ambient air to a second carbon dioxide removal structure; the second carbon dioxide removal structure comprising a sorbent supported upon a porous substrate and capable of releasably binding carbon dioxide to remove a predetermined portion of the carbon dioxide from the second admixed ambient air mixture; passing the second carbon dioxide removal structure into a second sealable carbon dioxide capture chamber, exhausting air from the second sealed capture chamber to reduce the air pressure therein, and passing steam, at a temperature of not greater than 120°C into and through the second carbon dioxide removal structure to strip carbon dioxide from the sorbent and regenerate the sorbent, while the steam condenses, and removing the stripped carbon dioxide from the second sealed capture chamber, so as to capture concentrated carbon dioxide; the first and second carbon dioxide removal structures being operated in tandem, such that when the first carbon dioxide removal structure has completed a regeneration cycle, and the second carbon dioxide removal structure is prepared to carry out its regeneration, the remaining steam in the first carbon dioxide capture chamber is flashed into the reduced pressure second carbon dioxide capture chamber in order to cool the first carbon dioxide removal structure and prewarm the second carbon dioxide removal structure prior to regeneration with saturated steam; and the first carbon dioxide removal structure is removed from the first capture chamber and moved into a flow of admixed ambient air; passing saturated steam into the second carbon dioxide capture chamber to regenerate the second carbon dioxide removal structure and removal of the carbon dioxide and condensed steam from the second carbon dioxide removal structure; and repeating the tandem operation so that the first carbon dioxide removal structure is returned to the first carbon dioxide capture chamber after adsorbing carbon dioxide from the flow of admixed air and the pressure in the first carbon dioxide capture chamber is reduced, and opened to the higher pressure in the second carbon dioxide capture chamber.