ADAC considers brake dust limits feasible

Petrol and diesel engines are becoming cleaner and cleaner, while engine emissions do not play a role in electric cars. All the more reason for other sources of particulate matter to come into focus. According to the ADAC, the planned Euro 7 emissions standard now includes limit values for brake abrasion for the first time.

Around 20 percent of a vehicle's particulate matter emissions come from the brakes, together with tire and road abrasion even two thirds. In Germany, around 8000 tons of brake abrasion are released every year, of which around 3000 tons are particles of the particularly health-relevant size PM2.5 (i.e. smaller than 2.5 micrometres), which can penetrate the lungs.

The planned Euro 7 standard stipulates a limit value of 7 mg/km for particulate emissions from brake wear. From 2035, the value is to be reduced to 3 mg/km. The brake dust emissions are determined on a flywheel mass test bench in a clean room. "Our measurements showed values between five and 20 milligrams of particulate matter per kilometer, depending on the brakes installed," explains Reinhard Kolke, Head of the ADAC Technical Center. The car club believes that a limit value of 7 mg/km is therefore feasible.

According to the expert, optimized friction lining mixtures and more wear-resistant brake discs can contribute to the reduction. An extraction or filter system on the brakes can also reduce particulate emissions. Compared to disc brakes, the closed system of drum brakes also retains particulate matter better. In electric and hybrid vehicles, improving recuperation performance can reduce abrasion. (aum)