'Invisible' microplastics spread in skies as global pollutant

Summary

Minuscule airborne plastic particles are spreading to all corners of the planet, penetrating deep into human bodies and sparking alarm among researchers of the relatively new subject matter. Studies are shedding light on the origins, transport mechanisms and impact of these pollutant microplastics, which are too small to be seen with the naked eye. They have been found in skies above Mount Fuji, in European rain, Arctic snow and within human bodies. These byproducts of human activity could also be fueling extreme weather conditions. “Marine microplastic pollution has drawn so much attention that the ocean has been assumed as the final destination for microplastics, but recent studies indicate that airborne plastic pollution is spreading at an alarming rate,” said Hiroshi Okochi, a Waseda University professor of environmental chemistry. Okochi leads a research team that has been studying airborne microplastics since 2017 and was the first to show that the pollutants had made their way into cloud water. According to studies conducted on how plastic waste is damaging marine creatures and the ocean environment, plastic litter that flows into seas degrades into “marine microplastics,” which measure 5 millimeters or less in particle size. By contrast, few studies are available on “airborne microplastics,” most of which measure less than 2.5 micrometers (0.0025 millimeter) across. One study published in 2016 found plastics in fiber form in rainwater in Paris, showing that plastic particles were wafting in the air. Okochi’s team in 2023 published a study that showed water in clouds covering the top of Mount Fuji contained 6.7 pieces of microplastics per liter. Airborne microplastics travel in different manners at different altitudes. In the free troposphere, an atmospheric layer extending above an altitude of 2,000 to 2,500 meters, substances are transported intercontinentally over long distances by prevailing westerly winds and other air currents. They are rarely affected ...