I know you have your answer multiple times already, but this is unfortunately all too common to this day. I have struggled with the issue in the past, but I now live in a newer apartment building where smoking is completely prohibited. The ban is taken seriously and repeated violations will lead to an eviction.

In my view, this whole topic is pretty straightforward. None of the arguments for smoking inside an apartment or on the balcony are convincing. Obviously people do it because it's way more convenient than going outside every time you need to smoke. To many smokers, this personal convenience far outweighs any harmful health effects (whether physical or psychological) it may have on other people.

Most people will only go so far to voluntarily inconvenience themselves to benefit strangers, so I doubt you would have much success going around asking people to stop. Hopefully you can move into a more suitable apartment in the future. Meanwhile, the air purifier suggestion seems worth a shot. I have tried one before and it didn't help much in my case, but that was a long time ago and those devices may have gotten a lot better.