Prototype cars in Korea clean roadside air and trap brake dust

Every car that rolls down a city street moves air through its grille and sheds dust from its brakes, and the driver never sees either. At the Korea Institute of Machinery and Materials (KIMM), a team led by Dr. BangWoo Han has tried to turn both flows into a cleaning job. Its prototype cars, a Kia Carnival and a Hyundai Sonata, now carry filters that pull fine particles out of the roadside air and catch brake dust before it escapes.

For years, automotive clean-air work went after the exhaust pipe. Particles that come from brakes and tires, known as nonexhaust emissions, have gained attention more recently, partly because electric and hydrogen-powered vehicles produce them too. Brake particle emissions are now regulated under Euro 7, the European standard for new vehicles, and the researchers expect their technology to find more uses as rules tighten.

The grille system works like an electrostatic filter. Particles entering through the grille receive an electric charge and are drawn onto collection plates. The collectors use carbon fibers thinner than a human hair, which lets them catch particles with a low electric current while producing little ozone. Driving provides the airflow, so no separate high-power blower is needed. When the car is parked over wireless power, its existing radiator fan can keep purifying the air around it. The brake device sits behind the caliper, and it relies on friction: the pads and discs give brake particles an electric charge on their own, so the collector needs neither a charger nor a suction fan.

In the team's tests, the grille system removed at least 95% of PM2.5 and at least 99% of coarser particles at 30 km/h, and kept the same performance at 50 km/h. Each vehicle purified about 1,800 m³ of air per hour. Fuel economy changed by no more than 1% after installation on both models. The brake collector captured 22.2 mg of brake wear particles per kilometer under the WLTC test cycle, which the team puts at about 10 g over 450 km. These figures come from the researchers' own vehicle trials and were published in the journal Tribology International.

For a city, the appeal is that the fleet already exists: every car on the road could, in principle, become a mobile filter without a separate street installation. The team plans to link the work with AirFive, one of KIMM's Five Flagship Brands, and to widen its use to improve urban air quality. But no price, production date or manufacturer commitment has been announced, and the tests covered two models only. Parked purification also requires spaces equipped with wireless power. The researchers say they still need to confirm performance and long-term durability under real driving conditions, so for now the results belong to a research team and two test cars.