SFGate

Dar I like the yellow walls with the shower curtain but a softer yellow might be nice. The sink vanity would be better in chocolate brown.

Here's a suggestion for the smoking issue: Look inside your vanity where the water and drain goes through the wall or floor. If there is any gap between the wall/floor seal it up. For small cracks use a silicone caulking product for larger gaps you may need to add wood, wall board or plaster to fill the gap then caulk. Also check around the toilet water supply.

Does it help to keep the drains bath and sink closed?

dupsl001 Cool comment on the yellow and chocolate brown.

There is a small gap around the sink drain where it goes into the wall. I've got some expanding foam that I will try to fill it up with. The smell is also in other areas of my condo and I already sealed up the kitchen sink in a similar fashion. Last weekend I ripped out the base board heating shields and sealed under those also because the smell was coming in through there.

It seems as though my condo is very negatively pressured, and potentially, with the winter "stack effect" in buildings, the air may be being pushed more into my unit, since I'm on the top floor, and carrying the smell below me with it.

Any other advice on the colors of the smell is much appreciated! I will update on the smell later today after I seal things up. Thanks!

dupsl001 And, there does not seem to be a different when either the tub or sink drains are open or closed.

Dar There are insulation rectangles that fit under the outlet plates. They are used to prevent cool air from infiltrating through outlets. Maybe they would help to prevent the smell from coming up through the wall into the outlet.

dupsl001 Got those on most of the outlets now. Most of the smell, I've discovered, is coming in through a small 1/4'' gap where my floor boards meet the corners in areas where there is no trim (for example, behind the dishwasher).

sacapuntaslapioz go with rich choclate brown for the walls and paint the vanity white.

Carolyn Albert-Kincl Design I agree with saca above to go with a dark brown such as SW2808 Rookwood Dark Brown on the walls and white on the vanity and med cabinet. Your white sink will look great.
Carolyn Albert-Kincl, ASID