Nonsmoker. (Of course, I've lived around big cities my whole life and have probably inhaled enough other airborne toxins to almost make up for it).

I never started, and nobody in my immediate family smokes. My grandfather smoked all his life and died of a heart attack a week before I was born (I was born in New Jersey because my mother, who had never done the childbearing thing before, didn't know not to travel at 7 1/2 months and went home for his funeral; I arrived early). He was very much looking forward to seeing his only daughter's first child.