ABSTRACT
Before rain falls, the earth releases a scent. The Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) termed it ‘petrichor’.
The smell itself comes about when increased humidity – a pre-cursor to rain – fills the pores of stones (rocks, soil, etc.) with tiny amounts of water. While it’s only a miniscule amount, it is enough to flush the oil from the stone and release petrichor into the air. This is further accelerated when actual rain arrives and makes contact with the earth, spreading the scent into the wind.1
