Thank you for the thoughtful responses, especially from the smokers. I agree that sometimes people who smoke are looked at in a pretty negative light, regardless of the situation.
Regarding the lawsuit, etc. I'm not the type to go that route, but I do understand it has a place in certain situations.
I will first kindly ask if she could do it outside, or if it was to take place inside, to confine it to 1 room. I think that is reasonable to ask, and then I could keep the door shut to that room at all times.
If she blows me off, I can always go to the realty company. I pay quite a bit above the average cinci rent for this place (please don't take this wrong...i lived in shitholes with 4 roommates for the past 8 years, my wife demanded a nicer place

) and the realty company sometimes has a hard time renting these out. I've lived here almost 2 years, so I think they may try to help reach some sort of agreement.
Should I hit dead ends both ways and have issues with breathing, then I don't have a choice. As Kelly mentioned, there is a clause regarding "enjoyment" or whatever. In my limited research, cases that do progress to court are usually ruled in the favor of the non-smoker. I think this would be true in my case, because this isn't a traditional apartment building. It's probably a renovated 100 year old house with air flow between all apartments.
I will keep you all updated as things unfold.