Airborne microplastics are now “all over the world,” according to a new study published in the Proceedings of the National Academy of Sciences. Studies have shown that billions of tons of plastic, discarded into oceans and land and broken down into small pieces, are being blown into the air by vehicles, sea and farmland. About 85 per cent of the microplastics found in the air are road traffic-related and may include plastic particles on vehicle tyres and brake pads, as well as plastic in crushed waste. About 10 per cent of the rest comes from the oceans and about 5 per cent from the soil.
Plastic pollution is one of the most pressing environmental problems of the 21st century, researchers say. Human-induced pollution causes the global plastic to form a natural cycle similar to the carbon cycle, which moves through the atmosphere, oceans and land, resulting in the “plasticization” of the Earth.
Microplastics are everywhere, researchers warn, and humans are even breathing, drinking and eating them. Previous studies have shown that pollution levels of microplastics will continue to rise rapidly. Scientists say this has raised concerns about the health effects of plastic build-up in the atmosphere, and inhalation of particulate matter can irritate lung tissue and lead to serious illness.
This time, the team obtained more than 300 samples of microplastics in the air from 11 sites in the western United States. The study found that microplastics in the air do not come directly from the city’s waste plastics, but are the result of plastic particles already present in the environment being blown up by road traffic and through the oceans and farmlands.
Professor Natalie Mohowald, of Cornell University in the US, one of the researchers, said: “We thought population centres were the main source of microplastics in the air, but that was not the case. ”
Further modelling studies on a global scale suggest that road traffic may be a major driver of microplastics in the air in Europe, South America and Australia, while wind in the fields is the main cause of microplastics in the air in Africa and Asia. Models show that smaller microplastics can stay in the atmosphere for a week, which is enough to cause them to be blown across the continent. In addition, microplastic pollution will also affect Antarctica.
The results suggest that even when microplastics in the atmosphere settle on land or in water, they may re-enter the atmosphere. It is estimated that the maximum concentration of microplastics in the atmosphere is over the ocean.
The researchers say the lack of observations in many parts of the world means their estimates are highly uncertain. In addition, current research lacks data on microplastics in the air above the ocean. Understanding the sources and consequences of microplastics in the atmosphere should be prioritized.