Why Can Turning on the Air Conditioning in a Car Lead to Suffocation?
2 Answers
When the engine is running, if the gasoline in the cylinders does not burn completely, it produces high concentrations of carbon monoxide. While the car is moving, the air passing through the air conditioning system creates convection, keeping the carbon monoxide concentration inside the car very low. However, when the car is stationary with the air conditioning still on and the windows and doors closed, the carbon monoxide emitted by the engine gradually accumulates, increasing its concentration, which can lead to poisoning or even death. Here are some precautions for sleeping in a car with the air conditioning on: 1. Park in an open area: The car should be parked in an open space, preferably with the front facing the wind direction, so that even if the engine is left running, the exhaust will be blown away. If parked in a confined space like an underground parking lot, exhaust fumes can seep into the car. 2. Leave a window slightly open: When sleeping with the air conditioning on, leave a 2-3 cm gap in the window to prevent suffocation or carbon monoxide poisoning. However, the gap should not be too large to prevent potential criminal activity. 3. Use the external air circulation mode: When sleeping in the car, it's best to turn on the external air circulation mode of the air conditioning. This mode draws in outside air, keeping the interior air circulating.
Having driven for over 20 years, I believe the stuffy feeling when using air conditioning is mainly due to poor air circulation inside the car. When you set the AC to recirculation mode, the same air keeps circulating without fresh oxygen entering, allowing carbon dioxide to gradually accumulate—similar to how you'd feel breathless in a sealed small room over time. Additionally, AC systems tend to accumulate dust or mold, blowing out air with odd smells or impurities that can irritate your respiratory system. Especially during long summer road trips, turning on the AC often makes me feel dizzy. I always recommend regularly cleaning the AC filter and switching to fresh air mode to introduce outdoor air—for example, opening windows for 10 seconds every half hour on highways for ventilation. This instantly relieves that suffocating sensation and protects health. AC maintenance is crucial—don't neglect it.
