Source: University of Birmingham

The following is excerpted from a piece posted by The University of Birmingham on a study concerning air pollution caused by vehicles beyond tailpipe emissions. The study on “non-exhaust” particles concentrates on brake dust, tire wear and road-surface wear.

BIRMINGHAM, U.K. – Under normal circumstances, when the world’s roads are not strangely quiet as a result of lockdowns to tackle COVID-19, much of the global South swelters under a fug of air pollution largely caused by vehicle emissions from gridlocked city streets.

Yet, air quality in ‘western’ countries benefits from improvements in emissions technology associated with the latest vehicles and an increasingly urgent drive – particularly in Europe and North America – towards electric propulsion.

Yet, even with the zero emissions technology promised by electric vehicles offering a vision free from nitrogen dioxide (NO2) and fine particulate matter (PM2.5) belching from internal combustion engines, there is one form of airborne pollutant that the switch to electricity cannot avoid, namely non-exhaust emissions (NEE) from road traffic.

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Particles are released into the air from brake and tire wear, road surface wear and road dust disturbed by a vehicle’s motion – regardless of the vehicle type or its mode of power. NEE contributes to ill-heath and premature mortality, yet there is no legislation in place to combat such emissions.

Whilst legislation has driven down emissions of particles from internal-combustion vehicles, the NEE proportion of traffic emissions has increased in the U.K.

Professor Roy Harrison OBE is a member of the U.K. Government’s Air Quality Expert Group (AQEG) and contributed to a recent study which notes that particles from brake wear, tire wear and road surface wear currently constitute 60 percent and 73 percent (by mass), respectively, of primary PM2.5 and PM10 emissions from road transport, and will become more dominant in the future.

“Non-exhaust particles from road traffic are certainly a bigger source of pollution in the UK than tailpipe emissions and, as traffic volumes continue to grow,  it is worrying that there is no regulation in place to govern NEE particles,” commented Professor Harrison. “We have a UK target of switching entirely to electric vehicles – in terms of new sales – by 2035. The aim of this is to reduce CO2 and air pollutant emissions, but there is currently a debate around electric and internal combustion vehicles regarding NEE particles.

“Battery-driven cars are heavier but generate power under braking and should emit fewer particles as regenerative braking does not rely on frictional wear of brake materials.”

The entire post can be viewed by clicking HERE.