I'm looking for advice ladies...

We are telling our parents within the next two weeks that we are expectinv and I want to tackle the smoking issue with his mother right away just so that the ground rules are clear from the beginning...

She smokes in her house and has been for years (you could see the discoloration in the roof and walls before they repainted this last fall...) and much of his extended family smokes as well (in the house...) She smoked through all three of her pregnancies and while her kids were growing up... (and I am certain that is the reason my husband has asthma...) Cigarette smoke bothers me enough on the best of days but now that I am pregnant it actually makes me feel like throwing up... You can smell it all through her house and we stay at her place when we stay the weekend in town to visit them... I feel like it is rude to ask her not to smoke in her own house and I feel that she may not understand the reasons why/feel I am overreacting if I do ask... But it is next to impossible not to breath it in when she smoke in the house unless I sit in another room two levels away for 20 mins while she has a smoke...

We could stay elsewhere on our weekends in town but I know that would break her heart as she so looks forward to us coming to town and staying with her (all her "babies" have moved out and her husband works out of town for long periods of time) so I don't want to take that away from her... I also want to make it clear that I am going to have clear guidelines for smokers when it comes to touching/seeing baby and I want her to know she will not be watching our baby for long periods of time in her smoke infested house... And am seriously considering asking people to come to our place if they want to see the baby cuz I don't want our child to be exposed to all second and third hand smoke (and sometimes first) unnecessarily...

I don't want her to feel like I am attacking her for smoking and keeping our child from her because of it (it is her first grandbaby so it is extra important) and I also don't want to come across as "Nazi-Mom" either... But I feel like exposing our child to cigarette smoke even just second or third hand is absolutely unnecessary - proven by science so it isn't even matter of opinion. I don't know where to draw the line between "over protective crazy" and "uncomfortably and dangerously relaxed" and it is causing me so much stress...

I'm sorry that was so long... I should also mention there have been other babies in and around the house over the years and growing up whose mothers were not concerned about the smoke exposure and I know I will be mocked for going "overboard". I just don't know how to find ground I am comfortable on in this situation without family getting bitter or mocking our caution...

Any advice from those who have lived through something similar?

****Update****

Thanks all for the advice, I am feeling better already about discussing our concerns with her when we announce the news. I don't feel like I am being too crazy anymore after hearing all your experiences! Baby's health is priority and she should understand that and be willing to work with us as a first time Grandma. Thanks again, ladies!