Synergism.
Synergism happens when two or more chemicals enter the body and create adverse side effects/health concerns because of their use together. The effects of the two chemicals together is greater than the sum of the effects of the two individual chemicals.
With increase in altitude atm pressure decreases... :)
So you know how it fits together, the ordering of the sequence.
Ammonia (NH3) is inorganic and would be the answer to your question