I think that a hygeine system would be a pretty cool system for the game to include where if you didn’t bathe regularly your scent level would increase. You could craft one of those japanese oil drum baths out of steel sheets or fill bathtubs with water from containers. Another thing could be taking sponge baths with rags or such to conserve water, or diving in deep water.
Another aspect that could contribute is if you were afflicted by the hot trait your clothes (and you) would be affected with the “sweaty” trait (similar to filthy clothing) or if you started bleeding you and your clothes would gain the “bloody” trait (similar to filthy clothes).
Sweat would increase your scent by a increasing number depending how long long you were sweaty, whereas “bloody” would increase your scent by a large but static amount.
Cooking food would also cause a good scent amount to a certain area if not airsealed and give you a minor scent increase for a short time, especially after cooking meat
Being covered in gore from melee combat (cutting would be a massive increase in filth whereas piercing and bashing would give lesser) or wearing filthy clothes could reduce your scent however
EDIT: factors like weather could contribute too such as windy days increasing scent and rain decreasing scent greatly