Abrasion from tyres, brakes and the road creates a lot of microplastics. This not only accumulates in soil and water, but is also released into the air, where it is absorbed by humans through the respiratory tract. So in addition to particulate matter, microplastics must also be regulated as quickly as possible. Could there soon be environmental zones to combat the small plastic particles?
Environmental zones for old vehicles with petrol and diesel engines are the norm in Europe. Hybrid and electric vehicles are generally allowed to enter the environmental zones. They are considered to have significantly lower emissions. This is true, at least for tailpipe emissions. But for some time now, experts have been demanding that non-exhaust emissions, i.e. the abrasion of tyres, brakes and the roads, must be regulated. Increasingly heavy hybrid and electric vehicles such as SUVs and luxury sedans lead to ever higher non-exhaust emissions.
New research from Cornell University in the USA has now confirmed that not only particulate matter but also microplastics enter the air through non-exhaust emissions. The small plastic particles do indeed enter the soil and waters via the road and from there into the sea. But they are also emitted directly from the road into the air, or get there via the sea spray. The results show that about 84% of airborne microplastics enter the air directly from roads, 11% via sea spray and 5% via dust from agricultural fields.
The Air Quality Expert Group (AQEG) had tested the microplastic emissions of a tyre last year. When new and at the prescribed pressure, it emitted about 5.8 grams of microplastics per kilometre into the air. The emissions from the exhaust were about 4.5 milligrams per kilometre, a factor of 1,000 less. If the tyres are older or do not have the prescribed pressure, the emissions from the tyre could be even higher.
The study shows that not only packaging and plastic goods are the main cause of microplastics in the environment. But microplastic emissions from vehicles are still completely unregulated and mostly unknown because they are difficult to measure. So the EU must act quickly to impose regulations on carmakers and adapt air quality directives. Then new rules could emerge in environmental zones, targeting not only tailpipe emissions but also particulate matter and microplastics from tyres and brakes. Many of the heavy hybrid and electric vehicles could then be banned from entering.
While this sounds harsh, such rules in environmental zones would lead the car industry to address the major problem of non-exhaust emissions, for example through lighter vehicles, more durable tyres or filter systems. With the current hybrid and electric vehicles, the problem of emissions has only been shifted from the exhaust to the tyres and brakes.