How to distinguish between internal and external air circulation in a car?

[SanPresley]

Methods to distinguish between internal and external air circulation in a car are: 1. Based on the symbols: The symbol for internal circulation is an arrow inside the car; the symbol for external circulation is an arrow entering the car from outside. 2. Based on the air circulation method: Internal circulation draws air from inside the car; external circulation draws air from outside the car, which is then cooled or heated by the air conditioning system before being blown out through the air vents. Internal circulation mode closes the airflow passage between the inside and outside of the car, forming an internal airflow circulation that effectively prevents external dust and harmful gases from entering the car and maintains the internal temperature. External circulation mode uses a fan to draw outside air into the car, and even if the fan is not turned on, airflow will still be drawn into the car while driving, replenishing fresh air inside the car.