The high temperature for several days was ended by a heavy rain, the sultry air was washed away, and a fresh breeze came to my face, with the smell of earth.
I don't know if you have noticed that there is always a smell of earth in the air after rain, and this smell is strongest when there is a long drought and showers. Whether it is a quiet country road, a busy city, or a lush forest road, the smell of soil in the air seems to be widespread after rain.
So, the question is, what is the smell of soil in the air after rain?
"Earthy flavor" is not just earthy flavor.
In fact, the air after the rain has a trace of earth smell, which was discovered very early and became the inspiration of many poets, thus being written into literary works. However, it was not until the19th century that this "earthy taste" attracted the attention of scientists.
In order to better describe this unique taste, scientists have given it a special name-"petrichor", which comes from Greek and means the smell emitted by stones.
At first, scientists attributed this smell to organic substances in the atmosphere or living or dead biological components in the soil. Later, in 188 1 year, scientists Berthelot and Andre discovered that the smell of this kind of soil could be separated and extracted from the soil by distillation, so this unique smell was also used in the creation of perfume (the smell was unique enough, with both the smell of wood and the smell of wood).
With further research, some scientists have found that myxobacteria cultured on the culture medium will also produce similar earthy smell, which may be related to the "earthy smell" in the air after rain.
It is found that the amount of hydrosol produced by the impact of light rain and moderate rain is much larger than that produced by downpour. Therefore, in light rain, the earthy smell in the air is often stronger.
Actinomyces are very common. They exist in every corner of the world, which is why this pleasant smell is so common after rain. At the same time, actinomycetes grow easily in wet soil and produce spores in dry soil, so the smell is strongest after the first rain at the end of dry season.
In the air after rain, besides the smell of earth, there are often other fresh smells mixed with it. Including the aromatic odor that may be generated by the reaction between weak acid rain and ground substances, and the odor generated by the essential oil volatilized by plants after the rain, which together constitute the unique odor in the air after the rain.