The DIY way would be a large mass of activated carbon in a tube and a PC fan to drive air through it. Blow your exhaled vapour into the fan and the carbon should do the rest.
Activated carbon is the key. It absorbs smells and must be replaced (not washed out which only traps dust and particulates).
HEPA ratings on the filter part (also a trap, must be changed when 'loaded' is also very important in overall performance. I use this guy:
https://www.amazon.com/Holmes-3-Spe...2284040&sr=8-20&keywords=air+cleaner+purifier
And I also follow WG's advice and have a small box of activated carbon sheets stacked up wired to the grill with a tube extending out. If I want prompt, effective trapping of smells I exhale directly into the tube so the carbon can capture it as quickly as possible. No need to wait for the smell to 'wonder in'. The unit itself is under the desk, behind a bunch of books and other clutter.
No, I don't use the ionizer feature.
OF
Edit: A couple of details for your consideration? "Vapor" as we define it is not really a vapor (individual gas molecules), but an aerosol (fine particles suspended in the air like smoke or fog), typically in the 'few to a few dozen micron range'. Very fine, you need
HEPA rated filters to trap them. Dust and pet dander filters won't cut it. You need finer holes in the filter than they offer.
Over time 'lingering smells' can evaporate from the particles to add to the problem of those in your exhaust and directly from the vape. That means an activated carbon surface to trap the molecules directly. This is basically the problem tobacco smokers face. Therefore looking for filter systems designed to attack those smells (like the unit above with the 'correct' filter) are the call. It's the filter(s) that count, not the box and fan that houses them.
Regards to all.
OF