It’s the rain and the dirt that mix together aromatically to set the mood for the day. The most refreshing of fragrances, the most ambrosial smell that brings us closer to emotions and sentiments as soft as the wet mud is one of the most cherished mysticism of nature. Now, the physics and logic, which in laymen terms would be some divine alchemy, is right there to back the romanticism up with science. How do we smell it? There is a common substance in the forests areas known as geosmin, produced by a bacteria called actinomycetes that swell the soil. Now, when the bacteria creates spores, the compound is secreted which are bounced into the air with force of the falling rain. The spores containing geosmin get splashed and spread in the air where they remain as we walk into them and to be received by the enticing fragrance.

Cultural perception of the earthly smell of rain:

It’s interesting find out that the people of Central Australian aboriginals, associate the earthly smell with the color green. The behavior was observed by Anthropologist Diana Young, of the University of Queensland, Australia who describes the phenomenon as a “cultural synthesia” – blending of two or more sensory organs as a result of evolution.

Other studies: The smell may also come in packets like champagne bubbles:

The rain drops fall and hit porous objects like soil and rocks that carry the aromatic component and form tiny air pockets. These air pockets rise up in the air like bubbles that release microscopic materials known as aerosols. Researchers believe that the rain-like aroma may be the result of the aerosols.

Hundreds of aerosols can spread in the air in less than a few micro seconds. Interestingly more aerosols are released during light and moderate rain than during heavy rainfall.