According to the results of a new study, the roads and vehicles that use them are responsible for 84% of the microplastics found in the atmosphere.
Researchers at Utah State University examined different sources of microplastic air pollution found in the western U.S. over a 14-month period.
These microscopic bits of plastic contamination are so pervasive that they affect the way plants grow, flow through the air we breathe, infiltrate the oceans, are found in the bowels of Antarctic insects, and even in the human bloodstream, the study authors warned.
The US team found that 84% of the microplastics in the atmosphere came from road dust, mainly tires, 11% from marine sprays and five% from agricultural soils.
The study authors found that most atmospheric microplastics came from roads, with sea spray (as bottles and packaging deteriorate) in second place.
Researchers at Utah State University examined different sources of microplastic air pollution found in the western U.S. over a 14-month period
Janice Brahney, Natalie Mahowald and colleagues examined the main sources of atmospheric microplastics, as well as the places where it concentrates.
They found microplastics from the earth on the surface of the ocean and plastic from the ocean to the earth, suggesting that it spreads through the atmosphere.
Hot spots for sources and accumulation of terrestrial microplastics included Europe, East Asia, the Middle East, India, and the United States, the study authors explained.
In general, the highest concentration of atmospheric microplastics was estimated over the ocean.
Depending on the size, the microplastics remained in the atmosphere for about an hour to 6.5 days, the latter long enough to take them to another continent.
Even the most remote continent on Earth, Antarctica, received microplastic pollution from the atmosphere, despite having zero microplastic emissions.
The findings suggest that even after atmospheric microplastics settle to the ground or water, they can re-enter the atmosphere.
Understanding how microplastics move through global systems is essential to solving the problem, Brahney said.
“Plastics enter the atmosphere … not directly from rubbish or landfills as you might expect … but from old, degraded waste that makes its way to large-scale atmospheric patterns,” the team explained.
Roads are a great source of atmospheric plastics, where vehicle tires are mixed and small pieces are thrown into the sky by a strong turbulence created by the vehicle.
Ocean waves are also full of insoluble plastic particles that used to be food wrappers, soda bottles and plastic bags.
These “inherited plastic” particles are directed toward the top layer of water and are agitated by waves and wind and catapulted into the air.
Agricultural and dust sources for airborne plastics are most important in North Africa and Eurasia, while road-based sources had a major impact on densely populated regions around the world.
These microscopic bits of plastic pollution are so ubiquitous that they affect the way plants grow, flow through the air we breathe, infiltrate the oceans, are found in the bowels of Antarctic insects, and even in the human bloodstream.
The US team found that 84% of the microplastics in the atmosphere came from road dust, mainly tires, 11% from marine sprays and five% from agricultural soils.
This study is important, Brahney said, but it’s just the beginning.
“Much more work is needed on this urgent issue to understand how different environments can influence the process: humid versus dry climates, mountainous regions and flat lands,” he said.
“The world has not stopped its production or use of plastic, so these issues become more urgent with each passing year.”
The findings have been published in the journal Proceedings of the National Academy of Sciences.