Do plants breath oxygen at night?
Plants require oxygen during the day as well, because respiration doesn’t stop. But they produce more oxygen during the day than they use up, so an excess of oxygen exists. At night, plants do not photosynthesise, but their respiration produces carbon dioxide (not monoxide). Plants require little oxygen during the night, far less than humans, so having a plant in your bedroom will not make much of a difference. Furthermore, when it’s night for someone, somebody else on the opposite side of Earth will have daytime, and there the plants will still produce oxygen. Due to atmospheric circulation, the oxygen will be distributed to the night side of the planet as well.
