I am in the same boat: the neighbor woman who lives in the apartment below me smokes, and I've been putting up with this for over 10 years. I am very sensitive to smoke, and I wonder how much this is exacerbating the headache. These past few days it has been particularly bad and I wonder if it's because I can't open my bedroom window as much in the wintertime Though even at this moment the window is opened with cold air coming in. The smoke seems to come in very profusely at the oddest hours, like 1 or 2 in the morning sometimes when I'm in bed. All I can do is slightly jar the window open, and I have my Holmes air purifier going at all hours, though not sure if this is a very good system.