Thank you for asking your query at DoctorSpring.
There are no evidence based studies which suggest that second-hand marijuana is dangerous. However in children constant exposure of second hand Marijuana MAY cause negative health effects. (NOT well studied, but possible risk – a risk to be avoided)
Now the level of risk is determined by two factors,
1. The frequency of the smoking. If you are getting the smell only occasionally (like 3-4 times a month) it should not be a major concern.
2. The proximity of the smoking area. If the apartments are very close / as in less than 20metes and/or has a shared wall or window the risk is higher.
But remember – Just ‘smell of Marijuana’ in the air, with no obvious smoke in immediate surroundings is not a risk factor, as the cannabinoid component is very less.
I recommend you to make a logical decision based on the above factors and consider discussing your concern with your neighbour in a friendly non-threatening manner.
Hope this helps
Please feel free to ask followup questions.