Car tyres are the largest source of particle emissions

Vehicle tyres are a source of both noise pollution and aerosol particles that can contribute to health problems and premature death. There are regulations governing noise pollution from tyres, but not for the emission of aerosol particles. A set of regulations to help limit particle emissions is however in progress, and VTI are involved in this process.

Modern cars and trucks produce less noise pollution and have lower emissions than older models. The fact is, that the largest source of both particle emissions and noise pollution from modern vehicles occurs from contact between the road surface and tyres.

Noise pollution and particles from tyres cause, for example, disturbed sleep and health conditions such as cardiovascular diseases. A high level of exposure to noise pollution from traffic can also hasten the onset of dementia. These factors can lead to premature death.

VTI is participating in the EU-project LEON-T, which is led by the Spanish Idiada Automotive Technology SA. The project is working to identify methods that can result in lower emissions and quieter tyres. A subproject, led by VTI, deals with developing a new truck tyre that uses spokes to support the weight of the vehicle, a so-called airless tyre. The aim is to reduce noise pollution and rolling resistance.

The VTI-researchers involved are Mats Gustafsson, Anders Genell and Ulf Sandberg. One of VTI's assignments is to investigate the connection between noise pollution from tyres and cardiovascular diseases.

"Here we are working together with the University of Gothenburg to look at how noise pollution affects sleep quality and indirectly cardiovascular diseases," says Mats Gustafsson, senior researcher at VTI.

The research is undertaken in a lab environment where test subjects are exposed to artificial noise pollution from tyres while they sleep. One of the aims is to identify specific sounds or tones that are more disruptive than others.

Within another project, VTI are compiling material that can form the basis of a standardised method for measuring tyre wear. This measurement is mainly connected to the levels of particle emissions from different types of tyres. In Sweden alone, tyre wear is calculated to be around 11,000 tonnes per year.

"Since 2010 the use of hazardous highly aromatic oils in tyres is prohibited. However, there are no limits for the emission of particles," says Mats Gustafsson.

For private vehicles there is also no labelling system that would help car owners chose tyres with lower particle emissions. Other important variables, for example noise and rolling resistance, already have a labelling system in place, according to Mats Gustafsson.

A possible explanation as to why regulations regarding particle emissions from tyres are not in place is that assigning responsibility is complicated.

"Tyre wear can, for example, be due to the tyre's construction and materials but also the nature of the road surface and the vehicle characteristics. It is not crystal clear where the responsibility lies."

Text: Johan Granath/ Redakta

Footnote: This article has been published in VTI Aktuellt 1/2023