It is commonly said that the smell of ozone is present after a rain storm. This is true, and some great data I read this week explains this further. Read the whole article here.
From the article, it explains that ozone can be be detected BEFORE it rains.
Before it rains, as the wind begins to pick up and the clouds thicken or roll in, you may become aware of a noticeably fresh scent in the air. That sharp, clear aroma is ozone, a molecule made up of three oxygen atoms bonded together (O3) whose name comes from the Greek verb for smell, ozein. It’s the same gas we associate with the layer of our atmosphere that protects us from too much sunlight. As unsettled weather approaches, ozone is carried to the ground in strong downdrafts that, once they hit the earth, move horizontally as strong, gusty winds that precede the arrival of the rain. That wind, or “gust front,” and the smell of ozone that’s carried in it, reaches your nose a short time before the approaching rain arrives.
The act of rain falling from the sky further creates an extreme downdraft of air and pulls more ozone gas to the surface of the earth so that after a rain, the odor of ozone is still present.
It is important to note that while ozone is generated from lightening in a rain storm this is not the cause of the majority of ozone detected at ground level. So, the next time you “smell” rain, you can thank God for the gift of ozone and science for helping us understand it!