Why the Smell of Rain is So Appealing
It turns out it’s not just gratitude that makes rain smell so appealing after a long period of dry weather. There’s actually some chemistry involved too. Bacteria, plants and even lightning can all play a role in the pleasant smell we experience after a thunderstorm; that of clean air and wet earth.
Known as “petrichor”, the scent has long been chased by scientists and even perfumers for its enduring appeal. The warm, earthy fragrance we experience when rain hits dry ground is produced by bacteria. “These critters are abundant in soil,” explained Prof Mark Buttner, head of molecular microbiology at the John Innes Centre. “So when you’re saying you smell damp soil, actually what you’re smelling is a molecule being made by a certain type of bacteria,” he said.
Drops of water hitting the ground cause that molecule, geosmin, to be released into the air, making it much more abundant after a rain shower. Now, geosmin is becoming more common as a perfume ingredient. Thunderstorms have their role to play too, creating the clean, sharp scent of ozone – caused by lightning and other electrical discharges in the atmosphere.