How do I prevent smoke from coming into my apartment?

I live in an apartment, which originally was a house that was converted into two apartments. The basement is an apartment and the upstairs is another apartment. I live upstairs and my downstairs neighbor smokes like a chimney. Smoking is inside is against the lease, but she continues to do so anyways. The smoke makes it difficult to sleep at night and gives us headaches. My roommates and I have asked her to stop numerous times, but she continues to ignore us. We have also called the landlord many times, but he doesn't do more than call her and tell her to stop, which she doesn't. Our apartment smells horrible all the time and our things are beginning to smell like smoke as well. Often after smoking, she thinks she's being clever by trying to cover up the smell with a horrible perfume that only makes the smell worse. I feel like I've run out of options. Is there some special kind of vent cover I can put in the floors to prevent the smoking from coming into my apartment or anything else I could possibly do, because I feel like I'm running out of options.