The clouds around Japan’s Mount Fuji and Mount Oyama contain concerning levels of the tiny plastic bits, and highlight how the pollution can be spread long distances, contaminating the planet’s crops and water via “plastic rainfall”. The plastic was so concentrated in the samples researchers collected that it is thought to be causing clouds to form while giving off greenhouse gasses.
“If the issue of ‘plastic air pollution’ is not addressed proactively, climate change and ecological risks may become a reality, causing irreversible and serious environmental damage in the future,” the study’s lead author, Hiroshi Okochi, a professor at Waseda University, said in a statement.
The peer-reviewed paper was published in Environmental Chemistry Letters, and the authors believe it is the first to check clouds for microplastics.
The pollution is made up of plastic particles smaller than five millimeters that are released from larger pieces of plastic during degradation. They are also intentionally added to some products, or discharged in industrial effluent. Tires are thought to be among the main sources, as are plastic beads used in personal care products. Recent research has found them to be widely accumulating across the globe – as much as 10m tons are estimated to end up in the oceans annually.
Humans and animals ingest or inhale large amounts of microplastics, which have been detected in human lungs, brains, hearts, blood, placentas, and feces. Their toxicity is still being studied, but new research that exposed mice to microplastic points to health issues, like behavioral changes, and other studies have found links to cancer and irritable bowel syndrome.
Waseda researchers gathered samples at altitudes ranging between 1,300-3,776 meters, which revealed nine types of polymers, like polyurethane, and one type of rubber. The cloud’s mist contained about 6.7 to 13.9 pieces of microplastics per litre, and among them was a large volume of “water loving” plastic bits, which suggests the pollution “plays a key role in rapid cloud formation, which may eventually affect the overall climate”, the authors wrote in a press release.
That is potentially a problem because microplastics degrade much faster when exposed to ultraviolet light in the upper atmosphere, and give off greenhouse gasses as they do. A high concentration of these microplastics in clouds in sensitive polar regions could throw off the ecological balance, the authors wrote.
The findings highlight how microplastics are highly mobile and can travel long distances through the air and environment. Previous research has found the material in rain, and the study’s authors say the main source of airborne plastics may be seaspray, or aerosols, that are released when waves crash or ocean bubbles burst.