How long does smoke smell linger?

So growing up in a household with a smoker, I know how *shudder* much that smell can get into EVERYTHING!  I also know it can stick around for quite some time. 

I ask because our house will randomly smell like smoke.  Now we are 99.9% certain the previous owners smoked in here maybe back in the 90's and I know the carpet and at least one closet probably still carry the smell a bit. 

But I am not talking about the "stale" smoke smell.  It randomly smells like someone just lit a cigarette right next to us.  At first we ignored it but one night we had just gotten home and were talking in the front room and both of us smelled it.  You know the smell.  Its different than the old smoke smell.

We've only smelled it in the very front (old dining room) and right near the TV where an old recliner was when we first looked at the house. 

It's not often but usually when it's cold outside.  And it's a VERY strong smell. 

I'm not scared of whatever it might be but I am curious.

If I had to guess its residual.  Just an imprint of a time long gone.  Anyways, I guess we will see as time goes on.




I JUST FOUND THIS IN MY DRAFTS AND AM POSTING IT NOW.....