Microplastics are tiny pieces – less than 5mm in size – that come from packaging, clothing, vehicles and other sources and have been detected on land, in water and in the air.
Recently, scientists from the French National Research Institute CNRS sampled the air at an altitude of 2,877 meters above sea level at the Pic du Midi Observatory in the French Pyrenees. This place is known as a “clean station” because it is very limited by the local climate and environment.
There, they tested 10,000 cubic meters of the air every week from June to October 2017 and found all samples contained microplastics. Using weather data, they calculated the trajectories of different air masses in front of each sample and discovered they were coming from sources as far away as North Africa and North America.
The study’s lead author, Steve Allen, of Dalhousie University in Canada, says that plastic particles can travel such distances because they can reach great heights.
He said: “Once it hits the troposphere, it’s like stepping on a super-fast highway.”
The study also points to sources of microplastics in the Mediterranean and Atlantic seas.
“Origin from the sea is the most interesting”, Allen said. “Plastic leaves the ocean and goes into the air at high altitudes – which shows that ultimately there is no concept of sinking for this plastic. It just moves around in an indeterminate cycle.”
While the amount of microplastics in the samples at the Pic du Midi station did not pose a health risk, study co-author Deonie Allen noted that the particles were small enough for humans to inhale.
And she says it’s a good idea to stop thinking that they won’t be present in a protected area away from pollution sources.
She said: “It questions our relationship with plastic, and adds that the problem is global.”
Allen says it also shows that some countries’ disposing of plastics by shipping them overseas is the wrong strategy.
“It will come back to you” researcher commented.