Windborne Microplastics Shed by Car Tires Are a Major Source of Ocean Pollution
Sat, April 17, 2021

Windborne Microplastics Shed by Car Tires Are a Major Source of Ocean Pollution


Vehicles are a major pollution contributor, producing carbon monoxide, nitrogen oxides, and other air pollution but cars may be doing more damage to the environment that what we know. A new study has found that the number of microplastics shed by car tires and brake pads as they wear down is blown from roads into the ocean every year.

Atmospheric microplastic transport

Andreas Stohl from the Norwegian Institute for Air Research and their team mentioned that terrestrial, freshwater, and marine pollution with microplastics has been discussed in several studies but atmospheric microplastic transport is often overlooked. This is why the group presented global simulations of air transport of tiny plastic particles produced by tire wear particles (TWPs) and brake wear particles (BPWs).

To estimate the number of microplastics shed by car tires and brake pads, the team used atmospheric circulation models. These models help assess how the tiny plastic particles are blown in different parts of the world. Stohl told The Guardian that the really small plastic particles are probably the most important not just in terms of ecological but also health consequences. This is because people can inhale the microplastics and the small particles can enter their blood vessels. He also pointed out how roads are a great source of microplastics, especially to remote areas and oceans.

They pointed out that about 30% of the emitted coarse of BWPs and 34% of the emitted coarse of TWPs were deposited in the world ocean. The magnitude of this pollution is similar to the total estimated direct riverine and direct transport of fibers and TWPs to the ocean. The region that may become a particularly sensitive receptor of such pollution is the Arctic. Since TWPs and BWPs also have light-absorbing properties, they may cause accelerated melting and warming of the cryosphere, which refers to the frozen water part of the planet.

Comment from an oceanographer

In an interview with The Guardian, oceanographer Erik van Sebille from the Utrecht University in the Netherlands said that the findings show how interconnected the pristine remote areas are with what people are doing in the roads and cities. Sebille is not a part of the research team but investigates the pathways and time scales of the global ocean circulation. His studies focus on how eddies and currents in the ocean transport nutrients and heat as well as plastics and marine organisms between different regions. He utilizes data observations from computer simulations of the oceans and the ocean itself to better understand how different regions of the ocean are connected.

Direct harm of plastic pollution to animals

In 2016, Sebille also revealed that the plastic dumped into the seas around the United Kingdom is carried into the Arctic within only two years. In that polar region is where the pollution does “extreme harm” to the fragile environment. This puts fish and wildlife in the area under pressure. Almost every bird and fish cut open for study, they find plastic inside their body. What’s alarming is that it is now hard to find an animal that, when cutting open, doesn’t have plastic inside it. The direct harm to animals caused by plastics includes oysters stopping reproduction, birds weighing down, and young fish starving. The microplastic become toxic and very potent chemicals, affecting the whole ecosystem.



When one group of animals are impacted, other species are also affected either because they are eating animals that have eaten plastic or they don’t have food anymore. It is also likely that humans may end up consuming plastic when they consume seafood. “We should be concerned,” Sebille said.

University of Strathclyde’s Deonie Allen, who was also not involved in the study, considers Stohl and the team’s work as well-conducted research. Results further show that there is a lot of microplastic pollution from other sources that most of us may not even think of and how far microplastics can move. Allen moreover said that the long-distance transport modeling paper reveals how significant the atmosphere is in the plastic pollution cycle.

Car tire and brake pollution: will it get worse?

Stohl said that the microplastic pollution caused by car tire and brake pollution is likely to get worse, foreseeing that more people will opt for electric cars. While these cars are cheaper to run and maintain, easy to power, and eco-friendly in terms of production, they are not better for the environment if we consider it in terms of the internal combustion. Electric cars could mean more wear on brakes and tires.

He went on to say that reducing microplastic pollution from cars is not easy. However, if it becomes a matter of concern, manufacturers will need to somehow respond. The author suggests that, in the meantime, people should reduce the use of plastics and make sure that if they do, it should be recycled.

A 2019 study estimated that 15 to 51 trillion microplastic particles are floating on the surface of the ocean. Scientific online publication Our World in Data likewise estimate that the emissions growth of microplastics to the oceans from 2020 to 2050 will amount to 549,000t. It referred to microplastics as buoyant plastic materials smaller than 0.5 centimeters in diameter.

Meanwhile, Statista’s ocean pollution by country data shows that China is the number one country for mismanaged plastic waste entering the sea. China is responsible for about 8.80M annual metric tons of mismanaged plastic waste polluting the oceans, followed by Indonesia (3.20M), Philippines (1.90M), and Vietnam (1.80M).



Research that focuses on microplastic pollution is difficult because of its seemingly endless sources and size. So far, there has been no accepted standard for sample processing, collection, reporting, and analysis. Last year, the San Francisco Bay Microplastics Project also found that the biggest source of microplastics in California coastal waters may come from car tires too. The National Oceanic and Atmospheric Administration also found microplastics in the stomachs of several marine organisms.

Before Stohl and the team’s study, we could only recognize human exposure to microplastic through the air. Now that we know that windborne microplastics are also a major source of ocean pollution, the public should consider it a great deal of concern not just for the aquatic animals but human health as well once exposed to potent chemicals for long periods.