What are the symbols for BMW's internal and external air circulation?

[VonRowan]

In BMW vehicles, the letter 'A' illuminated indicates external air circulation, while the letter 'M' illuminated represents internal air circulation. Below is an introduction to the related content: 1. Letter symbols: The central control button features both the letter 'A' and the letter 'M' on the same button. 2. Appearance shape: There is also a shape resembling the exterior of a vehicle, with a curved arrow inside. Below are the differences between internal and external air circulation in terms of closing the air intake: 1. Internal circulation: When using internal circulation, the vehicle's interior space acts like a sealed environment. Whether it's cold or hot air blown by the air conditioning, it circulates within the car, with no fresh air entering. 2. External circulation: When external circulation is turned on, fresh air from outside flows into the car, improving the air quality inside the vehicle, which is also a beneficial way to use it.