My Parents Smoke And I Smell Like Smoke. . .what do i do?!?

Okay so my parents have smoked for a long time and i am really concerned about thier health. . .and mine. And another thing is that i smell like smoke and i HATE that. I hate how my friends dont come over because it smells gross, i hate how i cant smell it but other people can, i hate having people over and seeing their reaction when they smell it, i hate hearing my mom and dad caugh wildly and having to hear it, i hate thinking about one of them getting cancer, or having a heart attack, or a stroke! I'v asked my mom if she could stop smoking many times and i can tell she has been trying hard to quit but she cant. . .her addiction is too strong. please help me! WHAT SHOULD I DO??!!!!!!