My imagination?

I think the chemicals from smoke can linger quite a while. Also, the smell can sort of get into your nostrils and although the actual smell has gone, your sense of smell still has the memory imprinted on it.

DGD and her partner both smoke, though not in my house. But when they paid a visit, it took me 24 hours, at least, to dispel the smell of tobacco. I hear from DS1 that they have now taken up 'vaping' which can at least emit an agreeable aroma, though I doubt if it's any better for their health.

Ah yes! Just realised you only opened the windows today, in which case you could well have still been smelling smoke. I always open windows and vacuum straight away after my visitor goes. It's a horrible smell - yuck!

You are definitely not imagining it oldwomen the particles from smoking get everywhere she may have had a cig just before she came in knowing she wouldn't get one for a while the said particles will be carried by her and deposited on your sofa or soft furnishings
I don't agree that smells don't linger what happens is our senses get used to it
I d do all the airing and opening that others have spoken of but add a neutraliser spray
I have a family of smokers next to me and one (unused) bedroom always smells it must come down the chimney (I have Victorian fireplaces in my bedrooms )

I remember going in the lift at work after a smoker had been in it, horrible. It wouldn't surprise me if it hung around for quite a while. I would open all windows even if it is cold for as long as you can bear it. Do you have a diffuser? They can be quite pleasant. M & S sell them.

It is very possible that your neighbour exuded a cigarette smoke smell as it would be on her clothes and even on her skin, and breath.

Maybe stand a drier with freshly washed washing in the room near the open window to add some freshness to the air. Unless is's so bad that you think the washing will end up smelling of smoke, too!

I am only guessing here, but perhaps it depends on how ingrained the smoker's clothing is with smoke particles. combined with how 'absorbent' the furniture is that they were sitting on!

Or could it be that you are overly sensitive to smoking / the residual smell? I know I am and find even a little hint really unpleasant and I do seem to detect it a mile off!

My father was a chain smoker and died from lung-cancer so I have been anti for a very long time.

I think it's highly unlikely that you can still smell smoke Oldwoman.
I have regular visits from a friend who has mental health problems and in addition to being a heavy smoker he rarely takes care of personal hygiene. To be honest he often smells rank (sometimes he asks me if he smells and I'm always honest with him) and as soon as he leaves I do all the things you describe. It can take several hours of having the window open, but certainly by the next day there are no lingering smells.

Last message got lost! Yes, tiny particles transfer, and people not normally around smokers notice.
I don't think air freshener helps. Vacuuming and airing does - if it's as nice at yours as here, I'd take cushions into the garden.
1-2 days it lasts in my experience. If gritting your teeth, then think she must enjoy your company a great deal to not have a cigarette over her coffee. I almost never have all but the lightest smokers in my house now,; and how I miss my dear BiL who only ever smoked outside, and never realised how the house smelled after he left, but his fantastic company made up for it!

Not sure about this one. D and her partner both smoke which they do in the garden, never indoors as our house is a smoke free zone. I have never detected smoke smell on either of them.
D's ex smoked and smelt like an old ashtray. However I never smelt anything indoors after he had visited.