Airborne Microplastics ‘Now Spiral Around the Globe’
Researchers find the tiny synthetic particles can stay aloft for nearly a week and travel large distances in the wind
Biology students may remember learning the water cycle, the carbon cycle or the nitrogen cycle. Now, new research suggests we may need to add “the plastic cycle” to the list of Earth’s list of biogeochemical processes, reports Damian Carrington for the Guardian.
The authors of the new paper, published this week in the journal Proceedings of the National Academy of Sciences, write “microplastic particles and fibers generated from the breakdown of mismanaged waste are now so prevalent that they cycle through the Earth in a manner akin to global biogeochemical cycles.” The authors focused on airborne microplastics, which they say “now spiral around the globe with distinct atmospheric, oceanic, cryospheric, and terrestrial residence times.”
The study’s models suggest some 1,100 tons of microplastic, defined as particles smaller than 0.2 inches, currently swirl over the western United States and many stay airborne for almost a week, reports Matt Simon for Wired. Some 84 percent of that plastic in the air comes from roads where cars and trucks kick microplastics up in their wakes, and, surprisingly, the offending stretches of asphalt tend to be located outside of major cities. Another 11 percent of the petrochemical miasma may waft in from the oceans, with dust from agricultural soils contributing the remaining five percent.
One of the major implications of these results is much of the plastic suspended in the atmosphere isn’t coming from fresh sources.
“We found a lot of legacy plastic pollution everywhere we looked; it travels in the atmosphere and it deposits all over the world,” says Janice Brahney, an environmental scientist at Utah State University and the study’s lead author, in a statement. “This plastic is not new from this year. It’s from what we’ve already dumped into the environment over several decades.”
In the ocean, as the tens of millions of tons of plastic already floating at sea break down into microscopic pieces, some of those minute particles take flight into the atmosphere via sea spray and get carried around the world by wind.