|The contents of this article have been cut.|
The subject matter of this article contains in-development information that was cut from the final version of an official and/or canonical source and appears in no other canonical source. It may also contain incomplete information since not all cut material is publicly known.
After the Seven Hour War
During the uprising
- "She pointed out a mounded shape, just visible through the enveloping smog; it looked like the shell of a vast slumber beetle; a streamlined mountain of corroded metal. From the density of the fumes, the stink of the air and the burning in his eyes, he suspected he had arrived at what Eli had called, "The Air Conditioner"."
- ―Alyx Vignette[src]
The Air Exchange, also known as the Air Conditioner, AirEx or the Combine's atmospheric reprocessor, is a location and chapter cut from Half-Life 2. It was to be set after the Depot, at the end of the Wasteland / Coast chapters, and before the Borealis, as the penultimate location of the third day. Prototyped and having all its maps made (although they are very messy and hard to fix), it was never finalized in order to let the team concentrate on areas more fruitful for gameplay.
Similar on the surface to common Earth factories, it was to be a Combine facility guarded by Combine Soldiers and Stalkers that had two different plotlines. One of them was to replace the air with noxious, murky gases, with its main reactor powered by an unknown blue energy source, probably the storyline predecessor of the Dark Energy reactor. Most of the air of the region was to be highly toxic so that Advisors could breath in, and most of the City 17 inhabitants were to wear gas masks. The second plotline involves the facility having a portal that displaces the earth's atmosphere to a low-pressure dimension, with some kind of turbines using the differential to generate power, like a hydroelectric plant that sort of acts like a dam except using air instead of water. As leader of the Conscripts, Captain Vance was to play a compromised and dangerous role protecting the facility ("
airex_03040506" also features several visgroups named after Vance, and a command center). Trucks of unknown use were to be found in the facility, along with refineries. Barnacles and Zombies were also to be found in several areas.
Early versions of the Air Exchange seemed to be much more focused on solving various puzzles with the facility's air mechanisms such as the vents. The map "
airex_rough puzzles", apparently the first Air Exchange map created, contains several visgroups with various puzzle concepts, mostly revolving around using air jets to push the player to inacessible places.
In this chapter, according from a script in Raising the Bar  Gordon Freeman was sleeping inside of a boxcar and then waiting up just to release that his HEV suit is non functioning, than explosions went off on the tracks and crashed into the wasteland. Later Alyx and her pet alien Skitch found him inside of the boxcar and left the vehicle while coming across Combine Soldiers. Then they would be ambushed by Combine Elites as they went close to the facility.
While Vance and his Conscripts were to launch an attack on the Weather Control, three chapters after the AirEx chapter, it is likely that some battle was to take place at the very start of the chapter, outside and inside the AirEx, since Vance was to protect the facility. It is also said that Eli Maxwell was the first to mention the AirEx existence to Gordon, probably in his slideshow.
Inside the facility, Gordon was to reach the top of the industrial tower where there was located what seemed to be a control room, and he might of then jump into a pool of industrial solvents at its base. Then he was to go inside the main reactor of the facility, might protected and operated by Stalkers, and sabotage its core (its design is almost identical to the Lambda Core from Half-Life), making the Air Exchange completely nonoperational and triggering the human uprising in City 17. Then, Gordon was to reach the shore, then the Arctic regions, and eventually reach the Borealis.
- The AirEx is part of the storyline set between the Scrapyard and the Hyperborea, the game timespan having been reduced to three days instead of the original four. Some elements were however recycled: blowing up the facility might of trigger the uprising familiar to the Nova Prospekt levels; reaching the top of the industrial tower and blowing up the core of the whole facility was recycled in the Citadel levels, along with the factory-like themes.
- The AirEx was last worked on in February 2002; the last AirEx map to be modified, the map "
temp3.vmf" (an overview of the AirEx, with a different design of the reactor) was last modified on that date.
- It is certain that the AirEx no longer exists in the retail game for both plotlines, confirmed by Marc Laidlaw. its effects were to make the advisors breath in earth while making the remaining humans to wear gas masks apparently constantly, as seen in other related early concepts. And fact that no humans are witnessed wearing said masks means that the idea was almost definitely removed completely.
Razor Train running through the Wasteland near the Air Exchange (reused in the skybox).
Fixed AirEx Truck.
Overwatch Soldiers near the Air Exchange reactor.
Tunnel conducting unknown energy near the Air Exchange reactor.
Ditto, with an unfinished model of the AirEx Truck parked on the highway.
 List of appearances
 See also
- Air Exchange mod - complete chapter on the Half-Life (pre-release) Project website (does not contain everything; requires registering and the leak)
|Half-Life 2 original storyline||Succeeded by|