Hi JLove,
I can identify. I have quit smoking but even when I did smoke-I use to live in an apartment where the back bedroom was surrounded by an enclosed alleyway. I lived on the 3rd floor and the neighbors on the first floor smoked. Some how all the cigarette smoke would chimney up the alleyway into my windows. The smell annoyed the hell out of me when I wasn't smoking and I had to turn off my fan (although it was summer) because it was sucking in all of the smell from the cigarette smoke.
I think getting a REALLY GOOD air purifier is the answer. Not one of those cheap ones but one from a company like Sharper Image works well and would get the smoke out of your air. You can also try putting a fan in the window so that the air blows out-open up a window from a side of the house where there's no smoke coming in to use to supply the fan with fresh air.
I wouldn't complain to your landlord unless you're ready to move if he says "Nope, can't do anything about it." Cause if the neighbors find out, they may retaliate-that's the last thing you need. They may smoke more, intentionally, just to harrass you and get you back for complaining to the landlord.
I'm sorry you have to go through this. Maybe one or two of the neighbors will move.
(((((((Jlove)))))))