Can a phantom smell show up only in one room?

Before treating it as paranormal, check ordinary sources that can be brief or easy to miss: airflow from a vent or window, a nearby appliance, stored fabrics, or something warming up. If it happens again, note the time, room, duration, and what was running. A second person can check the room while it’s happening, if one is available.

A smell with no clear source can also come from the sense of smell itself. Temporary phantom smells have several possible causes, and a single episode doesn’t identify one. If this keeps happening, changes, or comes with other symptoms, it’s worth discussing with a clinician rather than trying to diagnose it from the smell alone.

The fact that it feels vivid doesn’t by itself tell you where it’s coming from. I’d keep a simple log and avoid jumping straight to either a haunting or a medical explanation. If other people can’t detect it and it recurs, that gives you useful information to share with a health professional.