Why Does It Smell After it Rains? Scientists Now May Know the Answer

We all know that raindrops have no smell. However, it is common knowledge that the air takes on a fresh scent after a rain shower.

To determine what causes the smell and where the smell originates, a couple of researchers from MIT recorded raindrops hitting the ground in slow motion. The results they gathered were astonishing.

According to Washington Post, these raindrops contain particles of liquid trapped in gas which are called aerosols. These particles are then released when they hit the soil.

The researchers think that these particles contain bacteria and plant oils stored in soil. When the raindrops hit the soil, the particles are eventually released which then results in the scent known as "petrichor."

However, raindrops do not solely release that smell. The Washington Post also notes that the bubbles on the surface of wine and champagne release aerosols as these contain the particles mentioned above. This release of aerosol gives each beverage its signature smell.

Youngsoo Joung, the Postdoctoral researcher said, "Until now, people did not know that aerosols could be generated from raindrops on soil. This finding should be a good reference for future work, illuminating microbes and chemicals existing inside the soil and other natural materials, and how they can be delivered in the environment, and possible for humans."

The experiments also led to the discovery that more aerosols are produced during light rainfall. This also suggests that the petrichor smell is emitted more frequently when the rain hits the soil and the drops are more precise.

This discovery might also lead the researchers to study how the microorganisms like bacteria that live in the soil wind up in the air.