The Unique Fragrance Of Petrichor And Its Desert Roots

Something I have always loved about this time of year is the smell of rain coming in. Within minutes of a storm rolling in, the desert releases a smell so recognizable that everyone knows rain is on the way. This fragrance is known as petrichor, and it comes from a mix of oils, minerals,s and chemicals that build up during dry spells.

landscape photography of mountains

Plant oils

One of the major contributors to the iconic rain smell we know and love is plant oils. Arizona is home to over 60 different plants that produce chemicals known as volatile oils.

When these plats go a while without rain, these oils build up, and the second the moisture hits them, the earthy smell of these oils fills the air. Creosote bushes and Sonoran Desert flora are the most common and potent of these plants.

READ: Best Plants For Arizona Gardens: Peppers, Eggplants, And Pomegranates

Photo by Jannet Serhan on Unsplash

Soil

Dead microbes in the soil secrete unique smells that get lifted up in the air when the rain hits. According to the University of Arizona, soil in Arizona contains a chemical called geosmin. Geosmin is produced by dead microbes and can smell like a lot of different things, such as eucalyptus, cloves, and cinnamon. The human nose is extremely sensitive to the smell of geosim, which is especially potent when it rains.

READ: How Mesquite Trees Thrive In Arizona's Arid Climate

green grass field under white clouds during daytime

Minerals

Desert soil contains a lot of iron oxides, small traces of copper and zinc, and clay minerals. These chemicals not only make the soil the well-known reddish orange color it is, but they also absorb and hold volatile oils and geosmin. When it rains, and these minerals absorb water, they release these plant-derived chemicals, and sometimes they produce their own metallic smell as well.

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Photo by Daniel Tuttle on Unsplash

The iconic smell of rain we know and love here in Arizona is created from a variety of factors, from dead organic matter to plant oils to minerals. For anyone who has lived here long enough, the scent of rain is more than just a smell; it's home.

CONTINUE READING: What Causes Arizona's Sunsets to Look so Pretty?