I was sat at work wondering what ‘wild’ thing I should do this evening, half an hour later it started to rain and that familiar smell drifted through the window, rain on a warm spring day! Until recently I didn’t know this smell had a name, everyone always says it smells of rain but really we should be calling it ‘petrichor’.  Reading the Met Office website it says the term comes from the Greek words ‘petra’ – stone & ‘ichor’ –  golden fluid that was said to flow through the gods and the immortals veins in Greek mythology.

The actual origin of the smell is from the oils flushed from the pores of stones, rock, soil etc as moisture fills them. This starts before the rain falls when the humidity increases and then further increases when it rains, with the droplets hitting the ground spreading the scent in to the breeze.  The scent is carried in tiny air bubbles created by the raindrop when it contacts the ground, the bubbles then burst from the raindrop in a fizz of aerosols.  You will notice petrichor more during light rain, as in heavy rain the speed of the drops falling stops the creation of bubbles and thus the release of the aerosol and the scent we all love.