Don't do it. Your DD might resent her for it when shes older.
I'm 28, and when i was a child my parents only childcare option during school holidays, both half terms and the 6 weeks in summer, was for me and sister to go to my paternal grandparents.
My grandmother chain smoked CONSTANTLY.
The entire drive to her home she was smoking with the window barely cracked. All day the entire 9-5 she was smoking. As soon as one was finished, the next was lit, all day every day, with me sitting on the sofa right beside her. Then the drive back again, smoking the whole time.
Now i'm older and understand the risks im LIVID at how much smoke and therefore carcinogens i've inhaled due to her selfishness, and what damage it may have done or may still do to my health.
I should mention my mum was a 5 or so a day smoker herself until i was 9 or 10 but NEVER in the house or around us. When i was 20, 10 years after she quit, she was diagnosed with secondary brain cancer that originated as undiagnosed smoking related lung cancer. She died 2 months later, in the exact same way her dad before her (my maternal grandfather) died, from the secondary brain cancer that started as smoking related lung cancer.
I'm paranoid of dying the same way, that there is a pattern with my mum and grandad and the damage done from her smoke could develop into cancer years later just like it snuck up on my mum.
I don't blame my parents, it was their only option to send us to her, but she chose her own habit over the health of her young grandchildren, and i HATE her for it. We didnt speak for years, she was diagnosed terminal 2 days before my mum was but hers wasn't in her brain so she got 18 months compared to my mums 2, which felt so unfair. My mum passed at just 48, and i cant stop myself deducting my current age from my mums and wondering if thats all i have left, if smoking related cancer will take me too despite me never willingly having ever actually put one in my mouth. I'll panic about getting it til the day i die, and i'll never forgive her for that.