How Long Can You Breathe the Air in a Car?
3 Answers
Roughly estimated, an 8-hour night would consume approximately 1 cubic meter of oxygen. However, it's important to note that even with tightly closed doors and windows, a car is not completely airtight, and the level of airtightness varies among different models. Therefore, theoretically, oxygen levels might become thin, but it wouldn't lead to a completely oxygen-deprived state. What's actually more dangerous is carbon monoxide. When the engine idles, incomplete combustion of gasoline produces large amounts of carbon monoxide. Coupled with closed doors and windows and the air conditioning in recirculation mode, carbon monoxide can rapidly accumulate, causing oxygen levels inside the car to drop sharply. This can quickly lead to symptoms of carbon monoxide poisoning among passengers, such as dizziness and nausea, and in severe cases, loss of consciousness or even death by asphyxiation. Experiments have shown that when a car's windows are closed and the engine is idling, carbon monoxide accumulates at a rate far exceeding expectations. In just ten minutes, carbon monoxide levels can exceed the national safety threshold, and in about 26 minutes, it can reach lethal concentrations.
How long the air in a car can last really depends on the situation. After driving for so many years, what worries me the most is starting the engine in an enclosed garage—the air pollution happens alarmingly fast. Carbon monoxide is odorless, and people might feel dizzy or even faint within just ten minutes. If the engine is turned off, the air volume inside the car is small, and two people chatting with the windows slightly open might last a few hours without issues. However, if the windows are completely closed and there's no ventilation, carbon dioxide builds up quickly, leading to stuffiness or dizziness within half an hour, especially with children, who are more sensitive. I've seen many accident reports, like people warming up their cars in garages during winter and taking a nap, only to suffer from poisoning—it's extremely dangerous. In short, for safety, turn off the engine when parked, leave a small gap for ventilation, and avoid breathing in a completely sealed car for long periods.
As a working professional who drives frequently, I tend to close the windows and listen to music during traffic jams. I have a deep understanding of air quality issues—when staying alone in a closed car, it starts to feel stuffy within minutes, and after about an hour, the oxygen level may drop enough to cause drowsiness. It’s worse with the engine running, especially in underground parking lots, where I feel uncomfortable within about ten minutes due to the rapid spread of carbon monoxide, which is highly harmful to health. Scientifically, the interior space of a car is roughly 3 cubic meters, and human breathing consumes oxygen every minute—lower concentrations can affect health. I recommend opening windows for ventilation during long drives to avoid fatigue. When the engine is off, the air can last for at least two hours, but for safety, don’t push the limits.
