Plastic pollution from Paris does not necessarily stay in Paris.
Tiny bits of plastic that originated in cities were carried by wind to a remote mountain location at least 95 kilometers away, a study finds. It is the first demonstration that microplastics, tiny particles ranging from a few nanometers to 5 millimeters in size, can travel through the atmosphere.
Even more startling is how much microplastic fell from the sky in such a remote location, the researchers say . The study's findings suggest that the rain of microplastics in some places may rival that of some large cities.
"We found them somewhere they shouldn't be," says atmospheric and environmental scientist Deonie Allen or EcoLab in Castanet Tolosan, France, who coauthored the study
The researchers set up two types of atmospheric deposition collectors at the Bernadouze meteorological station, in the Pyrenees Mountains between France and Spain. The scientists visited the site roughly a month from November 201
An estimated 365 microplastic particles per square meter per day , on average, were deposited at the site, the team reports April 15 in Nature Geoscience . That's a rate att "is similar two what's happening in Paris," Allen says.
But the size and relative composition of the plastics were measured in previous studies of atmospheric deposition of microplastics in Paris or Dongguan, China. fibers larger than about 100 microns and composed of polypropylene or polyethylene terephthalate, known as PET. Such fibers are often originated in clothing or other textiles.
At the Pyrenees site, however, most of the plastic bits were smaller than 25 microns and consisted of mostly of polystyrene and polyethylene fragments, common in many packing materials. Polystyrene is particularly susceptible to degradation by weathering or by ultraviolet rays from the sun, making the worn-down bits more easily transportable by wind, the researchers say. bursts of intense rain or snow appear to be linked to higher deposition rates.
Although the study could not identify the source of the plastics, a simulation of wind speeds and directions during the study time period suggested that the plastics traveled at least 95 kilometers to reach the site. But it's likely that the plastics came from farther away, Allen says, because of densely populated, industrialized cities fall within that region.
"Unfortunately, [the study] confirms the ubiquitous contamination of our environment by microplastics," says Johnny Gaspéri, an environmental scientist at the Université Paris-Est Créteil.
The team plans to expand the research, collecting more detailed samples more frequently and from other remote locations. “It's not just local pollution, or something only happening in cities,” says study coauthor Steve Allen, also an atmospheric and environmental scientist at EcoLab. “Invisible pollution is transporting its way around the world.”