To paraphrase Shakespeare, something smells rotten in the state of New Jersey. 

They have never smelled of cigarettes when I've spoken to them, and that smell tends to linger.

I have been battling this concept myself.

However, if you are dealing with a normal seller without any experience, you're going to be looking at an uphill battle because investing may not be something that has crossed their mind.

If he ends up being your final choice that's great, but if not, no harm no foul.

Not letting fear win the battle and taking steps as I go along.

I guess they could do an air sample, but if it's bad enough you can smell it in a room with some visual evidence.  

(He lives in same building as landlord)My concern is I'm reading a lot of scams on how Chicago tenants try to work the system and the landlord is stuck in a battle for months.

As soon as I and renewed the lease the tenant wrote me this long message with all these thing wrong, including drain smells bad(she’s been putting bleach down the drain to kill the odor, the lights in the kitchen and bedroom are flickering(this ones easily fixable) & the bathroom floor is in-caving because of water damage(she suggested a new shower door).

It's an uphill battle, in such a popular location.