A modular portable oxygen generator, comprising: a reactor container having first vertical compartment and second vertical compartment; the first vertical compartment having an opening at top end being configured to house a cartridge, the cartridge housed in the first vertical compartment, a reactor enclosure, covering the opening at top end of the first vertical compartment, having an inward protrusion in center adapted to act as a cartridge trigger for triggering release of oxygen in the cartridge, a cartridge slot followed by the opening at top end, a cartridge cover surrounding the cartridge, an opening at one of a bottom, side and top of the first vertical compartment guarded by a hollow connector followed by a one-way valve adapted for flow of oxygen released in the cartridge, and a release ring attached to the hollow connector, where the release ring adapted to be pushed down to move the hollow connector; the second vertical compartment having a storage tank adapted to receive the oxygen released in the cartridge, a pressure gauge adapted to maintain pressure of the oxygen to be released, a humidifier adapted to humidify the oxygen to be released, and an outlet for the humidified oxygen; a pipe assembly connecting the hollow connector of the first vertical compartment and the storage tank; and a base structure sealing bottom of the first vertical compartment and the second vertical compartment. a reactor container having first vertical compartment and second vertical compartment; the first vertical compartment having an opening at top end being configured to house a cartridge, the cartridge housed in the first vertical compartment, a reactor enclosure, covering the opening at top end of the first vertical compartment, having an inward protrusion in center adapted to act as a cartridge trigger for triggering release of oxygen in the cartridge, a cartridge slot followed by the opening at top end, a cartridge cover surrounding the cartridge, an opening at one of a bottom, side and top of the first vertical compartment guarded by a hollow connector followed by a one-way valve adapted for flow of oxygen released in the cartridge, and a release ring attached to the hollow connector, where the release ring adapted to be pushed down to move the hollow connector; the second vertical compartment having a storage tank adapted to receive the oxygen released in the cartridge, a pressure gauge adapted to maintain pressure of the oxygen to be released, a humidifier adapted to humidify the oxygen to be released, and an outlet for the humidified oxygen; the first vertical compartment having an opening at top end being configured to house a cartridge, the cartridge housed in the first vertical compartment, a reactor enclosure, covering the opening at top end of the first vertical compartment, having an inward protrusion in center adapted to act as a cartridge trigger for triggering release of oxygen in the cartridge, a cartridge slot followed by the opening at top end, a cartridge cover surrounding the cartridge, an opening at one of a bottom, side and top of the first vertical compartment guarded by a hollow connector followed by a one-way valve adapted for flow of oxygen released in the cartridge, and a release ring attached to the hollow connector, where the release ring adapted to be pushed down to move the hollow connector; an opening at top end being configured to house a cartridge, the cartridge housed in the first vertical compartment, a reactor enclosure, covering the opening at top end of the first vertical compartment, having an inward protrusion in center adapted to act as a cartridge trigger for triggering release of oxygen in the cartridge, a cartridge slot followed by the opening at top end, a cartridge cover surrounding the cartridge, an opening at one of a bottom, side and top of the first vertical compartment guarded by a hollow connector followed by a one-way valve adapted for flow of oxygen released in the cartridge, and a release ring attached to the hollow connector, where the release ring adapted to be pushed down to move the hollow connector; the second vertical compartment having a storage tank adapted to receive the oxygen released in the cartridge, a pressure gauge adapted to maintain pressure of the oxygen to be released, a humidifier adapted to humidify the oxygen to be released, and an outlet for the humidified oxygen; a storage tank adapted to receive the oxygen released in the cartridge, a pressure gauge adapted to maintain pressure of the oxygen to be released, a humidifier adapted to humidify the oxygen to be released, and an outlet for the humidified oxygen; a pipe assembly connecting the hollow connector of the first vertical compartment and the storage tank; and a base structure sealing bottom of the first vertical compartment and the second vertical compartment.