Microplastics from the oceans detected in the air above the Pyrenees

Microplastics are going around the world. They can be transported between continents by high winds, highlights a study published Tuesday, December 21 in the journal Nature Communications. These pollutants of a few millimeters, mostly coming from the deterioration of plastic packaging, have already been found on Everest, in the Arctic, in the snow of the Alps, in rivers or in the middle of the oceans. Studies had also measured microplastics in the air in close proximity to the ground.

This time, researchers from the CNRS, the University of Grenoble Alpes and the University of Strathclyde (Scotland) looked for them in “pure” air, at altitude above the clouds. Their results show that the mountains are not spared.

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At the Pic du Midi observatory, perched at 2,877 meters in the French Pyrenees, samples were taken between June and October 2017, with a pump sucking 10,000 cubic meters of air per week. All contained microplastics, in amounts without immediate risk to health but significant in a presumed preserved area, where “One cannot easily attribute” this pollution has no local origin, write the researchers.

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Plastic from the oceans

To understand its origin, they calculated the trajectory of the different air masses sampled over the seven days preceding the samples. As a result, the pollutants originate in particular from the northwest of the African continent, passing over the Mediterranean, North America or the Atlantic Ocean.

These data confirm an intercontinental route, because the atmospheric zone studied, the free troposphere, acts as “A super-fast lane” over very large distances for particles, says Steve Allen, lead author of the study. For the researcher, it is the marine origin of a part of these particles which constitutes the most salient teaching of the study. “That plastic is pulled from the ocean to such altitudes shows that there is no possible storage sink, it goes around in circles in a perpetual cycle. It shows that we cannot just send the plastic abroad, because it will come back to you ” in another form.

Especially since some of the particles analyzed, of the order of a micron, “Are of a size that we can breathe”, adds Deonie Allen, also author of the study. These results “Show that it is indeed a global problem”, adds the researcher.

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The World with AFP

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