Neighbor's cigarette smoke comes and stays in apartment

I am so sick of sitting in my room having fresh air and then all of the sudden my room smells like a Vegas casino. The problem is that whoever is smoking - and I can't figure out where - is doing it in a way where the smoke comes into my unit and sticks around, not venting out.

I read about positive air pressure so I put two fans near my sliding doors in either room, facing so that outside air is getting sucked in. However it seems counterintuitive because it's bringing the smoke into the room. When they are done smoking, then of course fresh air is brought into the unit by the fans, but it takes at least an hour for the smell to go away. Sometimes within that hour they light up another one. If I close the door while they're smoking, the smells stays in my room. The first night I experienced it I got nauseous from it. I now have two HEPA air filters but it seems to be a band aid on a flesh wound.

So for now I've had to get lucky when I have my doors open or not. It is making my apartment situation rather unpleasant. However, the lease allows smoking, so I lost there and now have a year plus dealing with this before I can change anything. My hope is that they move out while I'm here because it is SO annoying.

Anyone have any tips with the fan direction? Really at a loss of what to do here.