Should the car air conditioning use internal or external circulation?
3 Answers
Whether to use internal or external circulation for the car air conditioning depends on the situation: use internal circulation for short trips and external circulation for long trips. Below is a relevant introduction to internal and external circulation: 1. Internal circulation means the air conditioning system is closed to external air and only uses the air inside the car for circulation. 2. External circulation means the car air conditioning system is open to external air, drawing in air from outside the car for circulation. Below is a relevant introduction to the functions of air conditioning: 1. It cools, heats, ventilates, and purifies the air inside the car. 2. It provides a comfortable environment for passengers, reduces driver fatigue, and improves driving safety.
When I encounter traffic jams while driving, I usually switch to the recirculation mode to prevent exhaust fumes and dust from outside, especially those from trucks, from entering the car. Not only do they smell unpleasant, but they also easily degrade the air quality inside the car. When driving faster on highways, I switch to the fresh air mode to let in some fresh air, which helps me feel more alert. During summer when using the air conditioning for cooling, I prioritize the recirculation mode for faster cooling and better fuel efficiency. However, after prolonged use, it's important to switch to the fresh air mode for a few minutes to prevent excessive carbon dioxide buildup, which can cause fatigue and drowsiness. In cases of smog or when driving through tunnels, I definitely stick to the recirculation mode for health protection. Actually, most cars have an automatic mode, which is very convenient with just a press of a button.
As a father, I'm most concerned about the impact of in-car air quality on my child. Using the recirculation mode is great when outside air pollution is severe, especially on city roads with lots of traffic lights, as it isolates polluted air. However, prolonged use of recirculation can decrease oxygen concentration, leading to drowsiness and affecting safety. Therefore, I recommend switching to fresh air mode for a few minutes every half hour. The fresh air mode is super useful during rainy days or when there are odors in the car, quickly ventilating to remove moisture and smells. My personal habit is to start the air conditioning with fresh air mode for 5 minutes to exchange air, then adjust according to the situation. Health is more important than convenience—don't forget to regularly clean the AC filter to prevent bacterial growth.
