What effect does cabin altitude have on passenger comfort?

Higher altitudes during flight can significantly affect passenger comfort primarily due to the decrease in atmospheric pressure and the corresponding drop in oxygen levels. As altitude increases, the partial pressure of oxygen decreases, leading to a reduced availability of oxygen for breathing. This can result in symptoms such as headaches, fatigue, and shortness of breath, collectively referred to as hypoxia.

Passengers may also experience discomfort from the physiological effects of rapid changes in cabin pressure during ascent and descent. This can include ear pain and sinuses discomfort. Therefore, higher altitudes not only influence how well passengers can breathe but also their overall comfort level during the flight.

The other options do not accurately reflect the relationship between cabin altitude and passenger comfort.