Our spare room doubles as a home gym (ie, the rowing machine lives in
there) and there are complaints from overnight guests (ie, my mother -
others are too polite) about the ambient residual aroma.

The window in there is open most of the time during the summer, but (so
I'm told) it still doesn't really do the job, and in weather like it is
now it's particularly awkward. So I was wondering about obtaining some
form of electrical de-odourising device - I mean something which will
actively filter out the niff, not just a plug-in air-freshener.

Is it right that these 'ionizer' devices are just snake oil? If so,
what do they use in public gyms; do they just rely on turning over the
air? Any suggestions?

If not it looks like time for an extractor fan through the wall, which
I'd rather avoid...

Thanks
--
David