House stinks of weed

I live in an apartment block of 6, my upstairs neighbour smokes marijuana constantly the entire block always smells of it, I leave my windows open all day and have automatic air fresheners but every room has a ventilation system in it that i believe links the apartments together. My house however stinks of weed, i dont smoke and live alone with my toddler, it smells the worst in the bsck bedroom so I changed that to my room and gave him the further away one but it still lingers. Any idea on how to make it smell less? I cant tell him not to smoke in his own house