Smells like stale cigarette smoke but is not

[Satha Palani]

The tenants who live in the unit next to mine complained of an odor that smells like stale cigarette smoke in their apartment. I checked it out and was able to smell it. At first I thought it was from the unit downstairs which is directly below. Checked out the downstairs unit and no one there had smoked indoors nor can I smell the odor .

I renovated the house shortly after I bought in 2017. New plumbing , roof , electrical etc. Tenants living there are the first to live in the Apartment post remodel. Couple with no kids. Both health nuts so I know it is not them smoking.

At first I though it might be mold but I don’t see water marks anywhere . The unit where the smell is shares an attic space with my own unit and I have not smelt anything so I am fairly sure it’s not in the attic either.

Tenants tell me the smell intensifies some days . Does anyone have any Ideas what it could be?

Many thanks,

Saths