Non Exhaust Emissions

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© Kevin McLaughlin

With the rise in electric car ownership, the sources of PM2.5 emissions will change from exhaust emissions to non-exhaust emissions, mainly tiny particles which are emitted from tyres and brakes. 

Testing firm Emissions Analytics performed some initial tyre wear testing using a popular family hatchback running on brand new, correctly inflated tyres, which found that the car emitted 5.8 grams of particles per kilometre. When compared with regulated exhaust emission limits of 4.5 milligrams per kilometre, the completely unregulated tyre wear emission is higher by a factor of over 1,000 (Air Quality News, 2020). 

The 2019 report Non-Exhaust Emissions from Road Traffic by the UK Government’s Air Quality Expert Group (AQEG) recommends “…as an immediate priority that non-exhaust emissions (NEEs) are recognised as a source of ambient concentrations of airborne PM, even for vehicles with zero exhaust emissions of particles” (AQEG, 2019).

Urgent action is needed to measure and reduce these emissions from previously unregulated sources.