While automakers and politicians scramble to transition to a zero-emissions sector in the coming years, the over two billion tires produced internationally may be a problem themselves. 

The Yale School of the Environment discovered that tire dust — small particles that break down and wear off of a tire over time — accounts for 78% of the ocean's microplastics.

Rebecca Sutton, an environmental scientist with the San Francisco Estuary Institute told Yale that "extremely high levels of microplastics" were found in stormwater, adding that "our estimated annual discharge of microplastics into San Francisco Bay from stormwater was seven trillion particles, and half of that was suspected tire particles."

The latest Yale analysis describes a decades-long study to determine the effects of various chemicals on fish on the West Coast, for example, and how some of those compounds can become deadly during typical tire wear and tear.

Tires are made of a combination of natural and synthetic rubbers and polymers that are intended to reduce the natural breakdown of a tire as it rolls over pavement. 

When tire particles inevitably make their way into road runoff and subsequently fish, some of them have unintentionally formed a hazardous cocktail. Researchers' determination to identify the culprits, such as a molecule called 6PPD, led them to discover how much tire dust is released when driving. 

According to a three-year study done in the UK, a car’s four tires churn out one trillion particles for every kilometer driven. And while two billion tires are made each year now, the Yale University report points out that number is expected to reach 3.4 billion by the end of the decade.

Microplastics in clouds cause 'plastic rainfall', infect everything

According to a new study, clouds now include microscopic bits of plastic, which are generating "plastic rainfall".

Earlier, AFP reported that the UN's environment chief warned against relying solely on recycling and called for a fundamental reconsideration of plastic use, as plastic production surges globally and is leading to increased pollution.

Scientists are concerned that tiny particles, smaller than 5 mm, known as microplastics, would contaminate "nearly everything we eat and drink."

Microplastics are a byproduct of the plastic waste that has choked lands and oceans as plastic degrades into smaller fragments and makes its way into the environment, human bodies, and wildlife.

Previous studies have connected these particles to illnesses and ailments such as cancer, infertility, and hormone disturbances.

Waseda University in Japan is the first to identify airborne microplastics in cloud water, as they conducted the first study to examine how microplastics affect cloud formation and their potential impact on the climate crisis and human health.