When it rains, it pours … microplastics, that is.
Researchers in Japan have discovered nine kinds of polymers and one rubber floating among the clouds — a worrying sign for the climate.
Intrepid teams of scientists climbed Mount Fuji and Mount Oyama to collect water from the foggy mist that veils the mountain tops.
Their samples were then brought to labs where advanced computer imaging parsed the physical and chemical properties of the cloud-derived water.
Each liter of water they collected held between 6.7 to 13.9 pieces of plastic, which measured from 7.1 micrometers up to 94.6 micrometers, or about the diameter of a human hair.
Their study, published in Environmental Chemistry Letters, also raised concerns about the abundance of hydrophilic polymers, which capture and hold water.
Researchers say these water-absorbing plastics may play an outsized role in the weather, while UV radiation from the sun breaks down the bonds of these toxic polymers, thus contributing to greenhouse gases in the atmosphere.
“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,” said lead author Hiroshi Okochi of Waseda University on Wednesday.
“To the best of our knowledge, this is the first report on airborne microplastics in cloud water,” the authors wrote in their report.
Microplastics are such particles that measure fewer than 5 millimeters and are particularly insidious for their tendency to turn up in the most unwelcome of places — from our drinking water and food supply to human organs and even a mother’s fetus.
There’s much we still don’t know about the effects of microplastic pollution on our health, though some studies suggest they’re linked to diseases such as dementia and irritable bowel syndrome.
This new report isn’t the first to document trash in the atmosphere. In 2019, rainbow bits of plastic were scattered across various locations in Colorado, including the peaks of Rocky Mountain National Park, after evidently coming back down to Earth with the rain.
US Geological Survey researchers counted plastics in 90% of all water collected during their study, aptly titled, “It’s Raining Plastics.”
In an interview with the Guardian at the time, lead USGS researcher Gregory Wetherbee warned, “There’s more plastic out there than meets the eye. It’s in the rain, it’s in the snow. It’s a part of our environment now.”