What is broken? Air vent or something else?

I live in a 3 story apartment building with two separate buildings. I'm on the basement level. The neighbor above my apartment smokes in his apartment. Somehow, the cigarette smell is coming into my bathroom. I have bronchial asthma which is triggered by allergens, dust, and smoke. My husband does not have any breathing problems. He used the bathroom this evening and now is he congested and wheezing. I used a face mask to use the bathroom. What is wrong that smoke smell is coming into our unit? We are so tired of bad electricity, appliances not working, black mold around the bathtub, and now this. We are moving out in June. I'm already starting to pack. Thanks for any answers.