35 weeks pregnant .. in laws smoking cigarettes. .. advice please

35 weeks pregnant wanted to know if I am being over dramatic. Decided to leave my motherInLaw house and stay with my mom until my apartment is ready. Two days ago before I left my step son came over my motherInLaw house. I came home after lunch with friend went to the kitchen and say my step son. Got him some chips and went upstairs to lay down. My feet were swelling. Few minutes later I smell cigarettes 3 different occasions. My step son is still down stairs ... I am shocked.. his grandmother would smoke cigarettes right in from of his face. No concern for his health. It really pissed me off.. I don't understand why a habit is more important than a child's health.

Is it wrong that when my daughter is born i plan on not leaving her with my mother In Law or sister In Law who also smokes in the house. I feel like if they don't care about my step sons health they damn sure won't care about my daughters either. And before I went to my moms house they were smoking in the house with me.