Scientifically elucidate the cause of the unique smell that occurs in the rain by observing water droplets with a high-speed camera

A MIT scholar photographed and analyzed the appearance of droplets falling to the ground with a slow motion movie, and found out the mechanism of a distinctive and unpleasant smell after heavy rainfall.

Rainfall can release aerosols, study finds | MIT News
http://newsoffice.mit.edu/2015/rainfall-can-release-aerosols-0114

Causes of odors generated from raindrops are explained in the following movie.

Rainfall can release aerosols, high-speed video shows - YouTube


After rain, it is often sunny and the unique smell drifts after the temperature rises.


Dr. Karen Buui of MIT has elucidated the mechanism of this scent phenomenon. It drifts fine particles using gas as a solventaerosolIt was the cause.


Like a bubble of champagne, gas is drifting in a liquid solventSolHowever, those in which the solvent is a gas and the solute is solid are called aerosols.


Dr. Buy, using rain water with a high speed camera, is porousaluminaI observed what kind of phenomenon happens when it falls on the surface.


The landed water droplet changes its shape while spreading ripples.


When the ripple fits, the wavy surface gradually becomes flat.


And, as ripples disappeared, it was confirmed that a very small size foam particle "aerosol" comes out from the surface.


Enlarging the water drop will look like this. Left is porous alumina, right is water drops falling on porous soil.


Fall.


It seems that water droplets spread more and more randomly on soil with more concavities and convexities than alumina.


And aerosol occurred in both alumina and soil.


The aerosol generated by falling raindrops is drifted by the wind in the natural environment and it drifts. And Dr. Bouy is thinking that the cause of bad odor after rain is because microorganisms of the soil are released into the air as solutes of aerosol.


The mechanism that this aerosol drifts in the air has the possibility to explain the occurrence of pathogenic Escherichia coli.


Dr. Buy is specialized in mechanical engineering and microbiology is not specialty. However, the discovery of the aerosol phenomenon by Dr. Bouy is thought that the law of nature should be acting on casual phenomenon of daily life, and by examining its mechanism, a good example of finding completely different new findings It seems likely to say that I will unconsciously hate a scientist's vigorous quest.