The amount of microplastics deposited from the air in the world’s oceans is likely to be comparable to that flowing from rivers, according to a new study. The report provides new insight into an important pathway that is spreading this pollution around the world.
“Some things are well known, like the quantity [of microplastics] lost clothes in a washing machine, “said Andreas Stohl, professor of general meteorology. at the University of Vienna and one of the co-authors of this study. “But our uncertainty ranges are really big and it takes a lot more work to compare different sources with each other.”
Roads are an important source of microplastics.
To model how microplastics move through the air, the team of researchers focused their attention on a relatively well-known source: our roads.
It is also one of the few sources of microplastics for which researchers can estimate global emissions.
“We know relatively accurately how much plastic is used in a tire and we know relatively well how much a tire wears out over its lifetime,” Stohl said. “There is also good information on road traffic, so we could distribute it globally.”
The researchers used two different models to calculate how much they are producing in different regions of the world.
They found that most of the particles are emitted in the eastern United States, northern Europe, major Chinese cities, and dense parts of the Middle East and Latin America. Globally, researchers estimated that more than 3 million tons of microplastics are produced from tire and brake wear.
After estimating the amount of these plastics that are generated worldwide, the researchers then used a scatter model to determine where the particles are. following.
However, according to Nikolaos Evangeliou, smaller particles can travel in the wind for much longer and often travel long distances. a principal investigator at the Norwegian Institute for Aerial Research and another co-author of this study.
Of these smaller tire plastics, approximately 57% land in the ocean, making them a major contributor to oceanic microplastics.
Microplastics Could Connect to Melting Arctic Ice
But not all microplastics in the air reach the ocean.
The study found that significant amounts of these tiny particles also land on snow and ice surfaces, including in the Arctic.
And as dark microplastic particles land in the Arctic, they could also be contributing to the fusion, the researchers said.
However, scientists cautioned that the effects of these deposits on ice should be studied further.
“Given the large uncertainties and that we have only considered one type of microplastics, there are probably more plastics in the Arctic than we know at the moment,” Stohl said. “This is not the main driver of Arctic fusion, but it is probably a small additional contribution of heat.”
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