I don't smoke (tobacco) in my house or my car since my wife started cancer treatments five years ago. (she quit smoking around 2 years ago...I'm still trying to quit...sort of) During the summer when it's too hot, (115 degrees) or winter when it's too cold, (right now...31 degrees) I smoke in my outdoors flower room. Always have, always will.

I'm sure the compounds (carbon monoxide, benzine...) from smoking are not optimal for growing anything, but I have never seen damage I could directly relate to asphyxiation or poisoning. Ever seen plants at the side of the 405 freeway? 24 hours a day the plants are bombarded with deisel and gas exhaust and they still grow. (despite poor waterings)

Is it a good idea to blow your smoke directly on the plants...? Probably not. On the other hand...I really doubt I'm doing enough damage to the plants, to worry one little bit about it.
Plus I'll be damned if I'm going to get frostbite, just to have a smoke, lol.