Dear Tom,
Why does the air sometimes smell like "rain"?
Laura Farr, Berwyn
Dear Laura,
Theories abound about the "smell of rain", but so far there is no definitive answer. Many feel that the dominant vegetation of a region contributes to the odor. The reaction between the moisture in the air and certain volatile substances on plants appears to be a partial explanation. Pine forests, for example, release terpenes (substances found in perfumes or medicines) into the air. Some olfactory specialists believe that moisture, warmth and low pressure, all harbingers of rain, enhance our sensitivity to smell while hastening the release of fragrant molecules from plants. Once the rain begins, the drops can kick up ground particles that add to the aroma. Some suggest that raindrops push earthy smelling gases produced by streptomyces bacteria out of the soil.
Why does the air sometimes smell like "rain"?
Laura Farr, Berwyn
Dear Laura,
Theories abound about the "smell of rain", but so far there is no definitive answer. Many feel that the dominant vegetation of a region contributes to the odor. The reaction between the moisture in the air and certain volatile substances on plants appears to be a partial explanation. Pine forests, for example, release terpenes (substances found in perfumes or medicines) into the air. Some olfactory specialists believe that moisture, warmth and low pressure, all harbingers of rain, enhance our sensitivity to smell while hastening the release of fragrant molecules from plants. Once the rain begins, the drops can kick up ground particles that add to the aroma. Some suggest that raindrops push earthy smelling gases produced by streptomyces bacteria out of the soil.
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