Should the Car's Air Conditioning Use Recirculation Mode?
3 Answers
When using the car's air conditioning, it is advisable to activate the recirculation mode. The relevant explanations are as follows: Usage guidelines: In urban areas, especially during congested traffic or rush hours when vehicle exhaust concentrations are high, selecting recirculation mode is recommended. On days when PM2.5 pollution is severe in certain regions (with PM2.5 levels above 50) and air quality is not rated as good, it is still advisable to use recirculation mode to prevent excessive inhalation of PM2.5 particles into the lungs. Air conditioning working principle: The car's air conditioning refrigeration system consists of a compressor, condenser, receiver-drier, expansion valve, evaporator, and blower fan. These components are connected by copper (or aluminum) pipes and high-pressure rubber hoses to form a sealed system. During operation, the refrigerant circulates through this closed system in different states.
I've driven a taxi for ten years, and using the air recirculation mode does cool down the car quickly, especially after the vehicle has been baking in the summer sun. Since recirculation only processes the existing air inside the car, the compressor doesn't have to work hard to cool down the hot outside air, making the cooling effect immediate. When stuck in traffic behind buses emitting exhaust or near chemical plants with foul odors, I immediately switch to recirculation to block external pollution. But I must remind you, never use recirculation mode the entire time. Once, I forgot to switch it off during a long trip, and after two hours, I felt dizzy—later I learned it was due to high carbon dioxide levels. I recommend switching back to fresh air mode on highways or in suburban areas once the temperature has dropped, to allow fresh air to circulate. Also, remember that using recirculation on rainy days can prevent window fogging, making driving much safer.
As the designated driver for family outings, I pay special attention to the impact of air conditioning on elderly and children. The recirculation mode effectively blocks external dust and pollen, making it ideal for family members with allergies. Last year when taking my child to the hospital during smoggy weather, keeping recirculation on throughout the journey reduced in-car PM2.5 levels by 60% compared to outside. However, after continuous recirculation for over 40 minutes, my child started rubbing eyes and feeling drowsy - tests showed oxygen levels had dropped. Now I set phone alarms to switch to fresh air mode for 5 minutes every half hour. I always activate recirculation before tunnels and ventilate immediately after exiting. When going to forest parks, I keep fresh air mode on throughout to enjoy nature's air - quieter than open windows and more energy efficient.
