Solvent-like or sweet odor that may come from coatings, refrigerants, adhesives or stored products.
First distinction
Note where the odor is strongest, whether it appears with rain, wind, heating, plumbing or ventilation, and whether closing a door changes it.
Do not mask the pattern
Fragrance can make the pathway harder to identify. Record timing before cleaning or moving stored material.
Next useful step
Compare nearby materials and systems, then use one controlled isolation check at a time.