What to do about weed smoking neighbour?

[addler]

I live in a converted church building made into flats.

One of the other flats has started smoking weed in the last month. I can smell it in every room of the flat and it really stinks. Tonight is the worst night, it's so strong. I've got a 5 day old DS and I hate that he's in an environment like this.

We're on the second floor and have a very beautiful high ceiling but it has holes in it which I assume go through to the other flat(s) on this floor that share the ceiling, and maybe that's where the smell is getting through?

I don't know if there's anything we can do. Some of the flats are rented with various landlords, some are owned, we rent and it's managed by a property management agency.

DP wants to go knocking on doors but I told him it wouldn't be the best idea as we don't know the neighbours, and there have been instances where mail has been stolen and bikes have been set on fire and washing lines destroyed so at least one flat in the building is a bit antisocial.

Can anyone advise? I have no idea how dangerous it is for DS, if the smell means it's harmful or not.

Block up the holes and keep some naice scented candles to cover the smell?

I'm currently renting too and this happened to me shortly after moving in, I had to put a towel along the bottom of our front door to try to block the smell a bit.
You aren't allowed to smoke at all in these flats so reported it to the landlord and also called 101 (I know not everyone would agree on that but it grates on you when you're paying huge amounts of money to live somewhere and it's all you can smell in your own home!). Especially as you're renting you could threaten the management company with you moving out of it's not sorted. If you are paying your rent in the current climate they should want to keep you.
How many flats are in your building OP? If you reported them is it likely they would no it's you?
I agree with your DP not discussing it with them as it could turn bad quickly and then you couldn't take it further as they know it's you (especially as they could be the anti-social ones. I hope you manage to get it sorted x

I reported my neighbour via 101 for smoking weed right under my bedroom window every evening. The police did actually go round and it does seem to have stopped.