“Or, better yet: Ideal Gas Law”
The Ideal Gas Law dos not apply because none of the gasses that we are discussing are ideal gases. Oxygen comes the closest, nitrogen is far away from it. CO2 is even further away.
An “Ideal Gas” in this context would be one who’s vapor pressure would reach zero when the temperature was absolute zero. That would make the pressure for delta T linear.
And no gas, in that context, is an Ideal Gas.