Air Exchange

The Air Exchange, also known as Air Conditioner, AirEx or Combine's atmospheric reprocessor, is a location and chapter cut from Half-Life 2. It was set after the "Depot" chapter, at the end of the Coast chapters. Prototyped and having most of its maps made, it was never finalized to let the team concentrate on areas more fruitful for gameplay.

Overview


Like the Citadel and the Depot and possibly the Weather Control, the AirEx was to be one of the many Air Exchanges spread on Earth by the Combine.

It was to be a Combine facility guarded by Combine Soldiers that was to replace the air by noxious, murky gases with its main reactor powered by an unknown blue energy source, probably the storyline predecessor of the Dark Energy. Most of the air of the region was to be highly toxic, and most of the City 17 inhabitants were to wear gas masks. As leader of the Conscripts, Captain Vance was to play a compromised and dangerous role protecting the facility.

In this chapter, Gordon Freeman was to arrive late into the second day, by train, and crash into a small depot located before the facility. There he was to meet Alyx and her pet alien Skitch. Then they would be attacked by Striders and Combine Super Soldiers.

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. Also, a piece of concept art also seems to take place at the start of the AirEx chapter, since the scene seems to be set in the Wasteland and featuring Antlions and Striders, with industrial buildings can be seen in the back. Even though Gordon seems to be alone in the picture, the Strider on the left is not firing at him (although it could be firing on Antlions). This scene was then likely to be set in the AirEx depot.

Inside the facility, Gordon was to reach the top of the highest tower and battle a Gunship and then jump into a pool of industrial solvents at its base. Then he was to go inside the main reactor of the facility, protected and operated by Stalkers, and sabotage its core, making the Air Exchange completely nonoperational and triggering the human uprising in City 17. Then, Gordon was to reach the shore on foot and proceed to the Borealis with Odell on a tugboat.

Fate



 * The AirEx was last worked on in February 2002; the last AirEx map to be modified, the map " " (an overview of the AirEx) was last modified on that date.


 * Blowing up the AirEx to trigger the uprising was merged with the Depot levels to make the Nova Prospekt levels; reaching the top of the highest tower and blowing up the core of the whole facility was recycled in the Citadel levels, as long with the factory-like themes.


 * It is uncertain whether or not the AirEx exists in the final storyline of the game, but as there are no in-game references to it, it is quite likely that it does not. This is especially true as its effects were to force the remaining humans to wear gas masks apparently constantly, as seen in other related early concepts. The fact that no humans are witnessed wearing said masks means that the idea was almost definitely removed completely.

Trivia
While a map of the AirEx intro can be found in several places across the Internet, it is a fan-made inspired by. No introduction map exists in the WC mappack, the player directly starting in. The Raising the Bar story fragment would have probably taken place in that missing map.

List of appearances

 * Half-Life 2: Raising the Bar