Can I ask the community group to switch off its diffuser without claiming it caused every migraine?

The organiser put a scent diffuser beside the sign-in book and said it made the borrowed meeting room feel welcoming. I asked whether we could leave it off for the next session.

I have diagnosed migraine. I have noticed attacks after several meetings in that room, but the evenings also involve bright lights, a late meal and a noisy journey home. I cannot honestly say the diffuser explains all of it.

[NHS guidance suggests keeping a migraine diary to explore possible triggers](https://www.nhs.uk/conditions/migraine/). I am keeping notes and discussing my pattern with my clinician. I would still like to try a meeting without the added fragrance.

The organiser says that unless I can prove a cause, it is unfair to take away something others enjoy. I have also offered to help make the room welcoming in other ways.

How would you ask for a trial change while being accurate about what you do and do not know?