There appears to be a divergence of views on the subject of whether plants in a bedroom are helpful or harmful to a person's health. My concern is whether the fact that plants release carbon dioxide, not oxygen, at night (and use oxgen at night) would significantly enough compromise the breathing air in a bedroom while a person is trying to sleep. A search of Google reveals the divergence of views, as follows: On the one hand, the knee-jerk answer seems to be that adding plants to a bedroom can only be helpful because plants clean the air of chemical toxins, add oxygen to the air during the day, do not release enough carbon dioxide at night or use enough oxgen at night to be harmful, and generally promote a cleaner indoor air environment in the bedroom. On the other hand, others contend that in Europe and apparently in New Mexico it is common knowledge that a person should not place plants in the bedroom because the plants release carbon dioxide at night and the presence of plants in the bedroom can be harmful and even fatal. Apparently some time ago in Britain, plants were removed from bedrooms at night for this reason. Google also revealed an article mentioning that regularly sleeping in a greenhouse would raise concerns for these reasons. (Feng shui experts also diverge on the matter with some saying plants in the bedroom are good, others saying they are bad, for reasons that are not biological per se in the particular realm of feng shui). (It should be noted that a handful of plants, such as the snake plant, release oxygen at night, not carbon dioxide, and have been suggested as aiding in sleep for this reason.) As a lay person, I am interested in learning whether there is more recent expertise out there on this subject and what people think in general about the matter who are famiiar with it, with a view towards providing the healthiest possible day-time and night-time environment in the bedroom. And, to that end, if plants do compromise the breathing air at night, what quantum of plants would we consider problematic in the average bedroom - one, two, three, four, five plants? Thank you.