MIT Researchers Discover What Really Causes That Pleasant Post-Rain Aroma [Video]

Have you ever wondered what’s behind that glorious post-rain smell? It turns out that the earthy and refreshing scent is all due to tiny air bubbles. Researchers say they’ve used high-speed photography to show the origin of the familiar earthy, sweet smell that lingers in the air following a rainstorm.

In the scientific world, that lingering scent is called “petrichor.” According to researchers findings at the Massachusetts Institute of Technology, USA Today recounts that “when rain hits a porous surface, like soil, tiny champagne-like bubbles of air are trapped and shoot upward.” The researchers have determined that those “aerosols” possibly release “aromatics” (causing that earthy scent) as well as other particles and elements present in soil, like bacteria and certain viruses.

Youngsoo Joung and Cullen R. Buie captured the visual of raindrops hitting 28 different surfaces and carefully observed what happened upon impact.

Buie, an assistant professor of mechanical engineering at MIT commented on his discovery.

“It’s a very common phenomenon, and it was intriguing to us that no one had observed this mechanism before.”

Buie added that the study may serve as a “jumping-off point for other research about chemicals in soil and how they can be delivered in the environment, and possibly to humans.” The team of researchers also notes that this discovery can determine why rainfall assists in spreading diseases such as Ecoli and viruses through the environment to humans.

Admittedly the researchers at MIT stated that it was, in fact, scientists in Australia that were first to “characterise the phenomenon,” as News.com informs, however, “until now it wasn’t known how the distinctive odour was released into the air.”

Buie went on to discuss how these findings are of great importance in regards to the spread of disease and the use of pesticides. ABC News shares his comments.

“Our research into this is only preliminary, so we can’t say anything for sure yet. But if true, this means that we’ll have to consider how pesticides, and other diseases could be affecting a larger area than thought because of chemicals being carried by aerosols.”

There is no use in feeling uneasy at learning this new information as Buie admits that 99.9 percent of the bacteria in soil is of no harm and does not actually cause disease. The study also concluded that more aerosols were released during a light rain shower as opposed to a heavy downpour.

The recent discoveries by the MIT research team were published in the journal Nature Communications.

[Feature image via the National Weather Network]