Pregnant surrounded by smokers

I’m a former smoker who quit when my husband and I decided to try for a baby. Currently, we live with family members who smoke in the house. unfortunately, these family members are very selfish and do not care that I’m pregnant because “they pay rent too”. We are trying to save up to buy a house, as well as, save up for the baby. My question is, has anyone else been in a similar situation? And what have you done to limit the exposure to the smoke? I was thinking about getting a large air purifier.