Hi, I’m 7 Weather Meteorologist Josh Nichols with this week’s edition of Josh’s Weather Academy, a segment where I answer some of your weather questions and take a deeper dive into Western New York’s weather whys.
Today we investigate what causes the smell of rain.
THERE ARE THREE PROCESSES THAT CAN CAUSE THAT VERY UNIQUE ODOR IN THE AIR. THE FIRST POSSIBILITY IS A SOIL PRODUCING BACTERIA SECREETING A SUBSTANCE CALLED GEOSMIN. THAT’S THAT DISTICNT EARTHY SCENT THAT COMES *AFTER* THE RAIN. THE SECOND POSSIBILITY COMES FROM THE OILS PRODUCED BY PLANTS WHEN IT IS DRY. RAIN CAUSES COMPOUNDS KNOWN AS PETRICHOR TO BE RELEASED FROM THESE OILS. THE HUMAN NOSE IS VERY SENSITIVE TO THIS ODOR AS IT IS WELL ASSOCIATED WITH FALLING RAIN. FINALLY, LIGHTNING CAN SPLIT ATOMS IN THE AIR INTO SMALLER ATOMS WHICH THEN COMBINE WITH OXYGEN TO MAKE OZONE WHICH HAS A DISTINCT ODOR *BEFORE* IT STARTS RAINING.
