How could you prevent smelling like cigarette smoke if you are secondhand?

I live with two people who smoke in one part of the house constantly. I open my windows at night because that's usually when they smoke. I close my closet door so my clothes don't smell like it & I take showers regularly. I feel like I'm being suffocated by smoke, and they don't care. They say "this is my house, I do what I want." So I'm on my own to try to find every possible way to prevent it. I even put a blanket over my face to try to avoid it. One of my friends asked me if I started smoking and nicely tried to put that I smelled like cigarette smoke. What do I do?