birdienl | 100 things challenge - 10: Smell after rain

You probably all experienced it, the lovely smell of a forest after rain. It's very distinctive, but what makes it smell so good?

It can be caused by multiple things. One of the main reasons is a group of bacteria called Actinomycetes. These very common bacteria grow in the soil, in damp and warm conditions. When the soil dries out, as in summer, the bacteria produce tiny spores. Rainfall kicks the spores up into the air and we breathe them in. The spores have a typical, earthy smell, which we associate with rainfall.

Another typical after-the-rain smell comes from the volatile oils plants and trees secrete. The oils collect on the ground and on rocks and when the rain reacts with the oils, it is carried as a gas through the air. Most people consider this a fresh and pleasant smell, and it even been bottled and sold for it's aromatic qualities!