Good point!
My best to you....
@mahgister / etal
With your car performance analogy, I suggest the air, or the O2, density is providing the largest influence. Hence the reason why some car engines are fitted with inlet manifold intercoolers.
H2O injection was a big thing in motorsport several years ago, because of the release of O2 into the combustion chamber increased power output for a given engine capacity, until it was banned by regulation.
Interesting about -ive ions. They will play a part as actual humidity rises.
Cheers,
BP