>>21 True, although it is fairly logical that if you can get enough dust into the atmosphere to block out a decent amount of sunlight..
At the very least, if you got enough dust up, you'd have the effect of the dust bowl, but much larger, which would make things bad enough by itself.
Anyway, yes, but that's assuming that there's actually a bio-dome like enviroment that people can safely hide away in. If they can't control their own enviroment, the cold alone would take quite a toll on anyone who survives the initial blast.