Post-Rain Perfume

“I saw God wash the world last night / With his sweet showers on high.” William L. Stidger’s poem elegantly describes how rain washes the world clean. And it certainly does seem that way after a shower—partly because of the fresh smell in the air.

That unusual but pleasant scent has a name: petrichor. It’s the mixture of several smells combined. Lightning, bacteria, and plants all play a part in producing this post-rain perfume.

During a thunderstorm, the electrical charge of lightning causes molecules in the air to split and rearrange. Some of the atoms re-form into a gas called ozone. The clean, sharp smell of ozone from the sky mingles with scents from the ground.

After a rain, you’re not just smelling damp soil—you’re smelling molecules made by bacteria in the dirt. These molecules, called geosmin, are found in most healthy soils. Raindrops form small bubbles when they hit the porous ground. When the bubbles float to the surface, they release aerosols that carry bacteria and scents, making geosmin more abundant after a rain shower.

Rain also stirs up compounds from plant oils. These compounds accumulate between rocks and soil during dry weather and release into the air when it rains.

Job 5:10 says, “He gives rain on the earth and sends waters on the fields.” Whether or not you’re partial to petrichor perfume, we can be grateful for the showers God sends to wash the world and make things grow.

This article is from Answers magazine, April–June, 2023, p. 24.