Hello, I don't speak Dutch fluently, so that I will write in English. If it is not accepted, I can edit and try writing in Dutch.
My downstairs neighbour(both apartments are owned by same person, I'm also a tenant) is smoking weed/hash a few times a day in his apartment and terras. When he smokes in his terras, the fume is directly coming to my apartment from the windows. Their floor was also smelling quite a lot, sometimes the smell was lingering to our floor from stairs.
With the start of the summer, I decided to talk with them about this issue directly. Before I wasn't opening my windows much, so I didn't want to take action.
He panicked, informed me wasn't aware of this problem and apologised. Also thanked me as I directly talked with him. He said he won't smoke in the terras if my window is open and gonna smoke in the apartment. Unfortunately, the problem still exists as the smell is also coming from his apartment through my windows. Not the whole fume but enough to disturb me, as it's hash. And I need to keep these windows open to cool down the apartment. He apologised again and told me gonna keep windows only slightly open. And told me if we can't solve this, he'll quit smoking in his unit. Unfortunately the problem wasn't solved so I talked with him again. I asked him to smoke outside if that's possible.
He told me I can't force him to smoke outside, it's legal for him to smoke inside the apartment, illegal if he smokes outside. He mentioned he's using it to relax from his psychiatric issue, it's known by his doctor as well etc. He said he'll try to smoke outside but can't promise. Since then, he still smokes in his apartment and the smell lingers to my unit especially in the nights.
I know personal use of weed is legal until you cause a public nuisance. Therefore I think it is not legal anymore for him. But I also heard cops won't do much as he's doing that at his home.
How likely this can be solved by my landlady(not a handy person), apartment management or even cops? Can he just states it's legal and keep doing that? Or still should I try to agree with him if it's a very gray zone legally?