Petrichor is the officiall name for the smell of rain. There are several factors that help make up this naturally producing smell. There is a type of bacteria found in the soil during moist conditions known as Actinobacteria. During dry conditions this bacteria will release spores, but once the soil is disturbed by the rainfall, some of the spores will be released into the air. Geosmin is another factor responsible for the smell of rain. It is an organic molecule that has the distinct earthy smell due to the bacteria it is composed of. Cyanobacteria and actinobacteria are the bacteria that produce geosmin and are released upon the death of microbes. The ozone, a variety of oils from the vegetation, and the overall acidity of rain are also factors involved in the petrichor smell.
|Petrichor Chemical Structure|
LOL yeah... don't be discouraged, I can barley pronounce it either and I had to learn this in college.
To read the more about the smell of rain and how the earth around us contributes click here: The smell of rain: petrichor explained