In a smoke-filled cabin, where is the "most breathable" air typically located?

In a smoke-filled cabin, the "most breathable" air is typically located approximately at armrest level. This positioning occurs because smoke tends to rise due to its lower density compared to air. As smoke ascends, it forms a layer near the ceiling, leaving a relative pocket of clearer air at mid-level, which corresponds to the height of most passengers' armrests. This is crucial for flight attendants and passengers during an emergency, as it highlights the importance of staying low and seeking breathable air at this height instead of closer to the floor or near the ceiling where the smoke accumulates.

The visibility at armrest level is also generally better than at floor level, where more smoke may be present, making it challenging to navigate or assist others effectively. Understanding this concept is vital for responding properly in a smoke-filled environment during an emergency.