Every gust of wind might be carrying microplastics, according to a new study published in the journal Nature Geoscience.

A team of researchers from France and Scotland wanted to find out how many microplastics could be found in the world’s most remote areas, where very little, if any, plastic is used.

So they traveled to the Pyrenees Mountains, which has long been a magnet for industrial pollutants carried by the wind, according to Quartz.

Take Action: Urge Philippine Mayors to Implement a Zero Waste Program in Their Cities

The team regularly visited a remote location on the French side of the mountains over a period of five months to collect data and found that each square meter of land collected 365 pieces of microplastic each day.

Across the entire Pyrenees, that could amount to billions of particles every day.

The researchers said that their research highlights the need to more comprehensively study plastic pollution and its effects on humans and ecosystems.

“Plastic litter is an ever-increasing global issue and one of this generation’s key environmental challenges,” the authors wrote in an introduction. “Microplastics have reached oceans via river transport on a global scale.”

Read More: Every Marine Animal Studied in This Report Contained Microplastics

“With the exception of two megacities, Paris and Dongguan, there is a lack of information on atmospheric microplastic deposition or transport,” they added.

In recent years, the scale of plastic pollution has come into alarming focus.

The amount of plastic produced each year weighs about as much as all of humanity, and it’s expected to rise by 40% over the next decade. Only around 9% of this plastic gets recycled, meaning 91% is disposed of in ways that can contaminate environments.

As plastic breaks down, it disintegrates into small particles known as microplastics.

There are an estimated 5.25 trillion microplastics in the world’s oceans, where they become magnets for toxins such as pesticides, and are routinely consumed by marine life.

News reports of animals dying from eating too much plastic have become more common in the past year. For example, a whale washed up in the Philippines with 88 pounds of plastic in its gut, and sea turtles regularly die from plastic consumption.

Read More: Even Insects Are Carrying Around Microplastics

The average human consumes an estimated 70,000 microplastics each year by eating food, drinking water, and breathing air teeming with particles.

Although the effects of this pollution have to be studied more closely, scientists worry that there could be health consequences, especially since plastic is often composed of carcinogenic materials.