I have a 2005 Acura TL. I have notice that the car has been riding lower to the ground. I also noticed that it has recently been quite cold. Would this affect the Volume of the gas inside the air shocks suspension in my car, therefore making it ride lower?
I am not familiar with the shocks used on an Acura TL, but I have dealt with several gas-filled shocks through the years. Getting the oil out so you can recycle the metal is quite an adventure. I painted the front of my body and about a third of the inside of my garage with oil once.
As for your question - In theory, yes there is a very slight difference in lift force when the shock is cold. In practice, gas filled shocks that I have dealt with tend to extend, but only with a pound or two of force. Therefore, they support only about 0.1% of your car’s weight. Changing the temperature/pressure in the shock by, say 100F (20% of absolute temperature) might change the extension force by a few ounces, but not enough to notice in ride height.
Why would you take the time to drain the oil out of the shocks? When they go to the metal recycler, they pass through a metal shreader that has a catch container for any liquids.
Tester
I think you’re talking about Charle’s Law:
Charles? Law states–when pressure and mass are constant, the volume varies directly the absolute temperature.
Boyle’s Law is: when temperature and mass are constant, the pressure varies inversely with the volume.
Anyways, if they’re the stock shocks the difference should be negligible. More likely your tires have dropped a few pounds with the temps. Have you checked them?
Shocks don’t control ride height, the coil springs do. If the car is riding lower you need to inspect the springs.
I think that you are correct that Charles’ law would apply in this case. The OP might try to have his state legistlature bail him out by repealing Charles’ law. While they are at it, the could repeal Boyle’s law as well. Acura owners could band together and have bumper stickers printed that read “Repeal Charles’ Law”. Ridiculous? I know a state where the value of pi was ruled to be 3 by its legislature.
I imagine the shocks have been tested all across the temperature range and there is no measurable difference in ride height.
"I know a state where the value of pi was ruled to be 3 by its legislature. "
That’s only half a pi. The full pi was cut into six pieces. 
The way I heard the story it was an agricultural state in the upper Midwest (not the dubious story about a Bible Belt legislator citing the story of Solomon’s Pool, which is given as 10 cubits across and 30 cubits around; but that was outer diameter and inner circumference). The Law made the volume of a silo for tax purposes equal to 3 x r-squared x h. That would encourage short fat silos, but I guess there are technical reasons to kep them tall and thin.