Maintaining bedroom carbon dioxide levels below 900 parts per million while sleeping is recommended for better sleep quality.

“There's clear data that once you pass 8 to 900 parts per million, it affects sleep quality. It increases the amount of times you wake up per hour. It decreases sleep efficiency and it decreases the way people feel when they wake up.”

“So like you really want to keep your bedroom levels of carbon dioxide below 900 parts per million while you're sleeping.”

“There's evidence that if the carbon dioxide in your room is over 900 parts per million at night while you're sleeping, this can affect sleep quality.”

“As CO₂ levels rise, the proportion of time spent in deep, restorative sleep drops.”

“Most studies report average overnight bedroom CO₂ levels between 750 and 1,300 ppm, but in rooms with closed windows and doors, CO₂ can reach 2,400–4,500 ppm, especially with two or more occupants.”

“Um, you want to make sure that you have proper ventilation in your room. One of the things that also happens in this is CO2. CO2 levels rise above 900 bars per million. This will significantly and dramatically affect everything from sleep onset, sleep quality, next day perceived fatigue next day arithmetic ability.”

“CO2 levels rise above 900 parts per million. This will significantly and dramatically affect everything from sleep onset, sleep quality, next day perceived fatigue, next day arithmetic ability.”