Low pressure cabin...
I used to work to a Nuclear Power Plant, that uses low pressure inside the nuclear buildings to keep the (probably) radioactive dust inside it.
It is accomplished through differential (negative) pressure in the HVAC system, like an OR or the CDC would do. This is just a few tenths of millibar of atmospheric pressure differential, but enough to cause the desired effect of avoiding external contamination. Some doors even have pressure relief valves and hinged lever "crowbars" soldered to the door frames to open them, should the system enter in panic mode and add LOTS more of pressure to system.
(We once did the math, and very few millibars would result in 50kgf of force applied on a door. "Smaller" workers had to actually use the crowbars to break the pressure seal...)
As a byproduct, any gasses... ahem... dissolved... on the personnel would leave them, far more often than outside.
Perhaps the boarding rooms on the airports could have a few millibars of differential ambient pressure subtracted from them. It would cause two things:
a) People would be acclimated to low pressure cabins far faster and;
b) People with a lot of dissolved gasses in their system would get rid of them before getting on board.
Biting the hand that feeds IT
