21.   People cannot live up there because the air is too thin and there is not enough oxygen to breathe.

22.   Starboard gybe is obviously safer than port, and clear air is vital.

23.   The air inside was rank with the fishy oils of stewing porpoise.

24.   The air is a toxic cocktail of exhaust fumes and noxious emissions from nearby factories.

25.   The air is clear and the mountains are pyramids of crystal glass.

26.   The air is dull gold with the past, a sad, melancholic silver gilt which colours the mood of city.

27.   The air is pungent with the smell of garlic fresh from the ground.

28.   The air is so thin up here I can hardly breathe.

29.   The air is sticky with a varnish of sea mist.

30.   The air is thick with conspiracy theories whenever the regime feels threatened.