Microplastics are carried by the wind to some of the most remote places on earth, according to new research involving University of East Anglia.
A newly published study shows how the wind carries these particles over great distances and much faster than water.
In the atmosphere, these microscopic pieces of plastic can travel from their point of origin to the farthest corners of the planet in a matter of days.
In 2018, Dr. Andrew Mayes from the UEA School of Chemistry developed a new way to detect microplastics in water and subsequently discovered microplastics in bottled water around the world.
He said: “Microplastics are small particles of plastic, which come from a variety of sources including cosmetics, clothing, industrial processes, packaging materials and the degradation of larger plastic items.
“Microplastics are known to be found in the environment at high levels, especially in aquatic and marine ecosystems, but also in the soil and in the air we breathe.
“We know that these tiny plastic particles have even reached the Arctic, Antarctica and the depths of the oceans, via ocean currents and rivers.
“We wanted to better understand how microplastics end up in the atmosphere and how they are then transported through the waters of our planet.”
The research, led by Dr Deonie Allen and Dr Steve Allen from the University of Strathclyde, involved collecting samples of microplastics from air, seawater and ice during a Polarstern expedition to the arctic last year.
Dr Mayes said: “Microplastics enter the atmosphere through human activities. Particles produced by road traffic tires and brakes or by exhaust gases from industrial processes rise into the atmosphere where they are carried by the winds.
“We found that the atmosphere mainly transports small microplastic particles, making it a much faster transport route that can lead to significant deposition in a wide range of ecosystems.”
The team found that up to 25 million metric tons of micro and nanoplastics are transported thousands of miles a year by sea air, snow, spray and fog, crossing countries, continents and the oceans.
And according to their estimates, this could reach 80 million metric tons per year by 2040.
Professor Peter Liss, from UEA’s School of Environmental Sciences, said: “Contrary to the usual assumption that microscopic pieces of plastic enter the ocean through rivers, our work demonstrates the importance of the atmosphere as an alternative entry route.
“It also defines a way to test this idea in future research. The potential implications of the atmospheric pathway for policies to reduce ocean plastic pollution are serious, as rivers and the atmosphere need to be approached in very different regulatory ways.
Collaborator Dr Melanie Bergmann from the Alfred Wegener Institute in Germany, said: “Air is a much more dynamic medium than water. As a result, micro and nanoplastics can penetrate the most remote and still largely untouched regions of our planet much faster.
Once there, the particles could affect the surface climate and the health of local ecosystems. For example, when these darker particles settle on snow and ice, they affect ice-albedo feedback, reducing their ability to reflect sunlight and promoting melting.
Likewise, darker patches of seawater absorb more solar energy, warming the ocean more. And in the atmosphere, microplastic particles can serve as condensation nuclei for water vapor, producing effects on cloud formation and, in the long run, on the climate.
The team also discovered that a significant number of these particles are transported by the marine environment.
Early analyzes show that microplastics from the coastal zone find their way into the ocean through eroded beach sand.
The combination of spray, wind and waves forms air bubbles in the water containing microplastics. When the bubbles burst, the particles end up in the atmosphere. As such, transport to remote and even polar regions could be due to the combination of atmospheric and maritime transport.
Therefore, it is important to understand the interactions between the atmosphere and the ocean, in order to determine what sizes of particles are transported and in what quantities.
Understanding and characterizing the cycles of microplastics between the ocean and the atmosphere will require joint efforts.
The study describes a global strategy to create a homogeneous and comparable database on the fluxes of micro and nanoplastics between the ocean and the atmosphere.
“There are so many aspects of the emissions, transport and effects of microplastics in the atmosphere that we still don’t fully understand,” says co-author Professor Tim.