About 50,000 tonnes of aerial microplastics from the road end up in the ocean each year, and 65,000 tonnes are dumped into the sea by rivers.
Microplastics thrown into the air by road transport could pollute the oceans as much as those from rivers, according to models published on Tuesday.
Many researchers have identified the presence of microplastics in all their forms around the oceans, to the bottom of the Marianas pit, the deepest known, and on earth, to the highest glaciers.
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As plastic production continues to grow, a new study published in Nature Communications is trying for the first time to estimate the amount of plastic from road traffic[[tire friction on the road and use of brakes]then dispersed in the air and redeposited elsewhere thanks to atmospheric currents.
End of race in the Arctic
The researchers evaluated the quantity of these particles derived from the petroleum industry (ethylene, propylene) produced by road transport, combined with simulations of atmospheric circulation. According to them, a third of these aerial microplastics from the road (around 50,000 tonnes, with a range of uncertainty between 40,000 and 100,000 tonnes) end up in the ocean each year, compared to 65,000 tonnes of microplastics discharged into the sea by the rivers. Even if they note a lack of field data that can validate their models.
“This atmospheric transport – an underestimated source, if not at all envisaged – has the same impact on the pollution of the oceans by microplastics as what is carried by the rivers”, affirms Nikolaos Evangeliou, of the Norwegian Institute for air research.
Emissions of microplastics from road traffic come mainly from North America, Europe and Southeast Asia. According to the study, a significant part of this pollution, transported by air, is likely to end its course in the Arctic, where the colored particles which absorb more rays of the sun than white snow, could have an impact on the melting ice.