Extremely dry air onboard aircraft
Cabin air in airplanes without continous humidity boost from an active humidification system will always be unhealthfully dry for humans. Air must be fresh with enough oxygen (read: low level of carbon dioxide). Therefore air is re-circulated with approx. 50% and mixed in with fresh air. But air at cruising altitude has no humidity. Consequently, air gradually gets more dry as fresh air intake exchanges humid ground air with super dry air.
Dehydration is a degenerative process with symptoms as listed below:
Humidity in air is an important condition for comfort climate.
Humidity is vital for our immune system
Humidity is better for our relax and sleep quality
Humidity increases our wellbeing and wellness
Humidity improves our sense to taste
Humidity reduces electrostatic electricity
Our taste changes and is different in the sky. Taste is taste buds and smell. Even short time exposure to extremely dry air affects the nose and mouth.
Actually up to 80% of what we consider taste is actually derived from smell.
The taste is built up around many very complex co-existing factors.