system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does smelling something like wasabi or horseradish immediately clear your sinuses?
gpt
The things that do that are irritants.  Basically, when your body comes in contact with them, it reacts- in the case of eyes and nose, your body tries to flush irritants by producing tears/mucous.

Your sinuses are blocked because mucous in them is thickened and staying in place instead of flowing- the natural flushing from the irritants mixes fresh moisture in to the existing blocking mucous, which allows it to flow properly and clear out of your sinuses.