Rainfall can release aerosols, study finds
Ever notice an earthy smell in the air after a light rain? Now scientists at MIT believe they may have identified the mechanism that releases this aroma, as well as other aerosols, into the environment. Using high-speed cameras, the researchers observed that when a raindrop hits a porous surface, it traps tiny air bubbles at the point of contact. As in a glass of champagne, the bubbles then shoot upward, ultimately bursting from the drop in a fizz of aerosols. The team was also able to predict the amount of aerosols released, based on the velocity of the raindrop and the permeability of the contact surface. The researchers suspect that in natural environments, aerosols may carry aromatic elements, along with bacteria and viruses stored in soil. These aerosols may be released during light or moderate rainfall, and then spread via gusts of wind. “Rain happens every day — it’s raining now, somewhere in the...