Transported by air masses, the pollutants taken from the Observatory of the Pic du Midi come from northwestern the African continent, passing over the Mediterranean, North America or the Atlantic Ocean.
Le Monde with AFP
Microplastics go around the world. They can be transported between continents by altitude winds, highlights a study published Tuesday, December 21 in the journal Nature Communications . These pollutants a few millimeters, mostly from the deterioration of plastic packaging, have already been found on the Everest, 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 the immediate vicinity of the soil.
This time, researchers from the CNRS, Grenoble Alps University and the University of Strathclyde (Scotland) sought them in “pure” air, at altitude above the clouds. Their results show that the mountains are not spared.
At the Observatory of the Pic du Midi, early at 2,877 meters in the French Pyrenees, samples were taken between June and October 2017, with a pump aspiring 10,000 cubic meters of air per week. All contained microplastics, in quantities without immediate risk for health but significant in a presumed preserved area, where “this pollution can not be easily attributed to any local origin, write researchers.
Plastic. Drawn oceans
To understand the source, they calculated the trajectory of the different air masses sampled over the seven days preceding the samples. Result, the pollutants come in northwestern the African continent, passing over the Mediterranean, North America or the Atlantic Ocean.
These data confirm an intercontinental path, because the atmospheric area studied, the free troposphere, acts as “a hyper-fast track” on very large distances for the particles, explains Steve Allen, the main author of the study. For the researcher, it is the marine origin on the one hand of these particles which constitutes the most salient teaching of the study. “That the plastic be drawn from the ocean to such altitudes shows that there are no possible storage wells, it turns in circles in a perpetual cycle. It shows that we can not just send Plastic abroad, because it will come back to you “in another form.
Especially since some of the analyzed particles, of the order of Micron, “are of a size that we can breathe,” added Deonie Allen, also the active of the study. These results “show that this is a global problem,” adds the researcher.