LEXINGTON, KY – Many Kentuckians have experienced the sensation of smelling rain before it begins to fall.
This phenomenon, common in rural areas with open landscapes, is caused by a combination of natural factors.
According to the American Chemical Society, one key contributor is petrichor, the distinct earthy smell produced when rain hits the ground. Petrichor is released when rain interacts with oils secreted by plants during dry periods.
In Kentucky, where agriculture and natural forests are abundant, this scent is especially prominent.
Another cause is ozone, a gas sometimes carried by winds from thunderstorms. Lightning can split oxygen molecules in the atmosphere, which then bond with other oxygen molecules to form ozone, according to the American Chemical Society.
As wind pushes the ozone-rich air toward the ground, it brings with it a sharp, fresh smell—often a sign of an approaching storm.
Lastly, geosmin, a compound produced by soil-dwelling bacteria, also contributes to the smell of rain, particularly in areas with fertile soil like Kentucky, according to the American Chemical Society.