I always get people telling me to look up at the light to sneeze, which I know is a phenomenon but I never hear anyone talk about mint.
Something about fresh air just tickles my nose and makes me sneeze. It’s especially great when I have a mouthful of minty toothpaste.
Or perhaps I’m just allergic to going outside.
During cold weather people are more likely to burn things in chimneys and etc.
The effect is subtle but extremely widespread. I also end up sneezing in cold air purely because that’s when people start burning stuff!
That wouldn’t explain the mint for me though.
I can’t say for certain, but I doubt particulates are the issue. Or I would be sneezing every time I walk close to a road.