Microplastics discovered in ‘pristine’ Pyrenees air

Microplastics have been detected in otherwise pristine mountain air in the Pyrenees.

Researchers said the tiny particles, which can be harmful to animals and humans, may have originated from as far away as North America, having been blown thousands of miles across the Atlantic in air currents.

Microplastics are already a depressingly common feature of rivers, oceans, and snow, but until now they have not been found in the high-altitude air along the mountain range that separates France and Spain.

An international research team including scientists from the University of Strathclyde in Scotland, the French National Centre for Scientific Research (CNRS) and Université Grenoble Alpes studied the air surrounding the Pic du Midi, a 2,87m peak in the French Pyrenees.

Having analysed the composition of 10,000 cubic metres of air captured weekly by a pump installed at the Pic du Midi Observatory, the team found a microplastic concentration of around one particle per 4 cubic metres.

The particles come primarily from packaging, the study published in the journal Nature Communications said.

Microplastics are fragments of plastic less than 5mm in length and have previously been discovered everywhere from the bodies of penguins in Antarctica to snow from the Alps and the Arctic.

Researchers described the presence of microplastics in the high mountain air – far from the usual sources of pollution – as “surprising”, but said that particles posed no direct threat to the local environment.

Lead author Dr Steve Allen, of the University of Birmingham, said: “While posing no direct threat, its presence far from sources of pollution is nonetheless surprising.

“The emerging threat of atmospheric microplastic pollution has prompted researchers to study areas previously considered beyond the reach of plastic.

“Investigating the range of transport is key to understanding the global extent of this problem.”

After running mathematical models of air mass trajectories, the scientists said it was likely the particles originated in Africa, North America, or the Atlantic Ocean.

They said this pointed to intercontinental atmospheric transport of microplastic, which raises the prospect of microplastics spreading widely even in remote and uninhabited regions.

The presence of microplastics in the ‘free troposphere’ – the lowest region of Earth’s atmosphere – shows they can travel further than previously feared.

Significantly, the team’s findings offer an explanation for the existence of microplastics at the poles and on Mount Everest.

Last year microplastics were discovered near the summit of Earth's highest mountain.

Researchers detected the particles at 8,440m above sea level in the Balcony of Mount Everest, which is around 400m below its peak.

The microplastics could have arrived either from the clothes and equipment of climbers, or been blown up the mountain by winds from nearby cities.

Microplastics have also been found in Antarctic sea ice. A study which analysed an ice core collected in East Antarctica in 2009 found 96 tiny particles of plastic identified from 14 different types of polymer.

However the particles were still relatively large in size suggesting that they had come from local pollution and had less time to break down than if they had been swept a long way by ocean currents.