And that is what is called the characteristic aroma that dry soils give off when they get wet because of the rain.
It is known that this happens mostly with fine and moderate rain and not so with heavy downpours
But, what is the reason for this smell that fascinates us?
Well, it is mainly due to the mixture of vegetable oils together with a chemical compound produced by Albert’s bacteria (Streptomyces coelicolor) called geosmin, which are released in the form of an aerosol when the rain hits the dry soil.
The raindrops hit the ground, catch small bubbles of air that carry the aforementioned compound; these air bubbles pass through the drop until they reach the air again, where they hatch releasing the chemical particles.
This bacteria, in addition to giving us its geosmin, has helped us a lot in the field of modern medicine since we have obtained a multitude of antibiotic, antitumor, anthelminthic and immunosuppressive agents.
Other species such as camelids, nematodes and insects benefit from it and its compound, since through its particular smell they know that there is water not far away.
To be fair and realistic, we must also mention another aspect not so good of our beloved petrichor and is that other bacteria and viruses not as beneficial as our Albert bacteria also spread by this means, producing diseases.
Fortunately, our immune system is quite advanced and it can practically be said that we can continue to enjoy one of our favorite scents without fear of getting sick because of it.
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