Smoke from BBQ’s and smoking are the same ‘nuisance’ not always policed within bylaws. If you feel brave enough have you considered writing an initial friendly note bring your concern to your neighbors attention? It’s a good first proactive step and perhaps the offending smoker is unaware of their consequence. Additional to that consider a cheap fire alarm on your balcony (seriously!). If it triggers often enough it’s sure to annoy them, and others, to the amount of smoke causing it, and hopefully that might bring some correction by them or others now sharing the pain. All the best with it. Cheers, C.