From time to time folks ask us to identify the source of an odor. This task is nearly impossible through the internet, so should these questions be off topic?
- How to solve a known smell problem is on topic.
- Techniques a homeowners can use to track down the source of a smell could be on topic (but only needs a single question of which all others would be dups).
- Asking "what is this thing I'm smelling" I'd recommend as off topic for not having enough information to answer.