Petrichor and Ozone: Unraveling the Aromatic Secrets of Impending Rain

 Do you possess the ability to smell impending rain? While some individuals swear by their knack for detecting rain's arrival through scent, others remain skeptical. Nonetheless, science supports the existence of this phenomenon, primarily due to petrichor.

Petrichor is the distinct aroma of rain on dry earth, particularly noticeable after periods of drought. Derived from the Greek words "petros" (meaning stone) and "ichor" (the fluid flowing through the veins of ancient gods), the term was first coined in 1964 by mineralogists Isabel Joy Bear and Richard Thomas. Many people list petrichor among their favorite scents, but its appeal to humans and animals remained a mystery until scientists discovered its connection to a soil bacterium called Streptomyces, which produces a compound called geosmin.

In 2015, researchers found that when raindrops hit a surface, they flatten out, trapping air pockets in soil pores. As these pockets burst, they release aerosols carrying traces of geosmin, which can travel great distances before rain clouds arrive. These geosmin particles are likely what people with a keen sense of smell detect as rain approaches.

In addition to petrichor, the presence of ozone in the wind contributes to the scent of incoming rain. Ozone has a sweeter scent compared to petrichor's earthy aroma and may signal heavy rain as storm-driven downward currents carry ozone to ground level, where humans can detect it/