The electrical room in the basement of the condo building I live (3 floors + basement, top floor has a mezzanine, 8 units total, in Montreal, Canada) has walls not finished. See photos.

There are cracks in the corners that weren't finished, so basically free air flows into the walls. I wonder if this has a function, or it was just laziness from the builder to save time. 

My concern with these cracks is that due chimney effect the air flows to my unit (top floor). I have to keep on top of other units so they periodically fill the P traps that dry (especially the emergency one, next to the hot water tank, that one is never used). BTW: I do not discard that there is a crack in the vent system, but again, the smell goes up, from within the walls. I already got two different companies checking for mold, and a plumber who wants to do a smoke test, but the condo association just doesn't smell anything (according to them). So I am left with no options.

I'd like to minimize the flow of air. I am hoping that by trapping the air they will get the smell themselves and/or less air goes into my unit.

Are these openings something that we can fill with silicone and be done with? Any recommendations on how to proceed?



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  [1]: https://i.sstatic.net/QNJJK.jpg
  [2]: https://i.sstatic.net/CFTBx.jpg
  [3]: https://i.sstatic.net/FPv6l.jpg
  [4]: https://i.sstatic.net/xU7W7.jpg