More China trains

We are on another Chinese train. This time from Beijing on the way to Xian.
  It's great, being an air conditioned train they don't allow smoking in the carriages. Stupidly they encourage it between the carriages (which are closed in so the train is like a big tunnel) and the people don't shut any doors so they might as well let people smoke in the carriages anyway. It is quite disgusting not having a choice of even 1 smoke free area. Also there are no openable windows so if you want any fresh air there in nothing you can do. Hopefully I won't get too sick.