The Science of Petrichor

Petrichor is the earthy scent when rain falls on dry soil. The word combines Greek terms for stone and fluid.

Australian researchers Isabel Joy Bear and Richard Grenfell Thomas introduced the term in a 1964 Nature paper. Argillaceous odour was a hard sell.

Petrichor is a natural mixture released by rain.

Thomas Lambe Phipson reported this in The Chemical News on 17 April 1891. He blamed flower fragrances absorbed into soil pores.

During dry periods, plants exude compounds that clay soils and rocks absorb. Clay soils have a surprisingly good memory.

Research in 2015 found raindrops striking porous surfaces trap air bubbles. These bubbles rise and burst as aerosols carrying the scent.

In 1965, Bear and Thomas suggested these components also slow seed germination and early plant growth. Aromatherapy that actively stunts you.

Streptomyces bacteria produce geosmin that attracts springtails. Humans sense geosmin at extremely low concentrations.