I just have one question. Is it ever explained in the campaign how people are still able to breathe on LV-426 without suits after the atmospheric processor got blown up at the end of Aliens?

I thought the whole point of the atmospheric processor was to create an oxygen rich environment so that people could breathe without suits. It's not exactly like there's crap tons of plants and trees around that place.

Sorry for double post, don't know why it made two threads... Mods can you take this thread down and leave the other one up?

Nope. There is no explanation.