From polluting the depths of the Mariana Trench to the top of Mount Everest, microplastics have now infiltrated the clean air as well. A team of researchers have found these plastic particles invading the air surrounding Pic du Midi at an altitude of 2,877 meter in the French Pyrenees.

Scientists from CNRS, Université Grenoble Alpes and the University of Strathclyde, Scotland analysed the composition of 10,000 cubic meters of air on a weekly basis. The air came from a pump installed at the Pic du Midi Observatory. Researchers found microplastic concentration of approximately one particle per four cubic meters of air.

Researchers said that this microplastic came predominantly from packaging and while it poses no direct threat to the health of people, its presence at such an altitude is surprising.

“Mathematical models of air mass trajectories used by the scientists indicate that the particles originated in Africa, North America, or the Atlantic Ocean, which indicates intercontinental atmospheric transport of microplastic,” researchers said in a statement, adding that a new stage in the microplastic life cycle and offer an explanation for their presence at the poles, on Mount Everest, or in other remote regions of our planet.

Researchers said that the evidence illustrates that microplastics are present in the planetary boundary layer (PBL), at least at the sites tested, but how far these particles can travel is at least partially dependent on the altitude they can reach within the atmospheric environment.

“The next logical question to ask is how ubiquitous is the microplastic pollution in our atmosphere and has it reached the free troposphere and what is the extent of free tropospheric MP transport?” they paper published in Nature Communications read.