Oceans, lakes and rivers often contain a large number of microplastic particles on their surface and impacting raindrops cause many droplets with an almost equally high concentration of microplastics to be thrown up into the air. When they evaporate in the air, the particles enter the atmosphere.
Researchers from the University of Bayreuth have investigated the phenomenon and found that when a raindrop hits a water surface, droplets from a small ring-shaped area around the impact site are thrown into the air.
They originate from a depth of a few millimetres below the water surface. The microplastic particles contained in the droplets have almost the same concentration as that in this narrow layer of water.
The trajectories and flight duration of the particles showed that water from raindrops, which is free of microplastics, ends up in the oceans, while water containing plastics from the oceans ends up in the air.
The droplets are suspended in the air...