We have all heard almost to the point of frustration about climate change, pollution and how bad cars powered by fossil fuels are.
We are all exhorted to consider using an electric vehicle, or a hybrid so as to cut our carbon footprint, and stop climate change.
Obviously, all of this is deserving of support, and climate change is a very real threat, as is the increase in health problems as a result of the toxic gases in vehicle exhausts.
However, there is a sinister, yet little-publicised threat which may prove to be even more injurious to health and the marine environment, even if it has little impact on greenhouse gases and climate change.
Yes, you did read correctly. Tyres are in the top ten of nasty pollutants that contaminate the world with micro-particles.
Tyres. Those innocuous black things attached to the wheel rims of your car, van, motorcycle, truck or bus.
We all know that tyres wear out – as we all have to buy them now and again, if we are to stay safe and legal.
So, what happens to the worn bits of tyre? Well, they are eroded by the road surface and are released as micro-fibres, particulates that are fine enough to form as a dust on the road surface.
Subsequently, rain water washes these microfibres into the drains and sewage systems, where they ultimately make their way into the maritime environment – yes, rivers, lakes, reservoirs and oceans.
Much publicity is generated around single use plastics in the oceans, but little publicity is around related to this almost invisible pollution.
Some of the particles are small enough and light enough to be dragged up off the road surface by the aerodynamic wake of passing vehicles, and may be suspended for periods of time, allowing them to be blown by the wind over quite large distances.
It is estimated that annually 68,000 tonnes of microplastics are generated by tyre tread erosion in the UK alone, with 7,000 to 19,000 tonnes entering the surface water system. Research is currently being undertaken in the UK to deepen our understanding of the migration of tyre generated microparticles into the maritime environment.
It may not be common knowledge but tyres are not constructed from pure natural rubber, but consist of 60-70% synthetic rubber – made with our old friends, the hydrocarbons, so the emitted micro-particles are not readily biodegradable.
Unfortunately, the qualities that makes tyres suitable, such as good grip, good braking qualities, and good car handling qualities rely on the tyre gripping the road surface through friction.
Friction between the road surface and the tyre tread actually causes the erosion of the rubber, and leads to the problem. The interaction also erodes the road surface, and any road marking paint on it too – but that’s another story!
Tyre particles vary in size and composition, so it would challenge even Agatha Christie’s Poirot to identify and track how these particles behave, and where they go once they have been shed.
Such particles will be dispersed widely around roads and byways, drifted by winds and the effects of vehicle aerodynamics, washed into various drains, culverts and waterways by rain.
Once in the water system the particles will exhibit different levels of buoyancy, and some will float onwards into estuaries and ultimately into oceans, and others will sink to the bottom and become part of the estuary sediment.
It is estimated that up to 10% of tyre wear particulate matter is released as airborne particles, which will settle over land masses, thus polluting them too.
What can we, the driving public do to minimise the effects of this?
Firstly, we can modify our driving behaviour to reduce the loads that our tyres are under.
We can make efforts to accelerate and decelerate gently and progressively, we can make sure the tyres are correctly inflated and remove un-necessary loads from the vehicle. This would help.
We could operate a smaller vehicle with a smaller engine and a lower mass.
This is a pipe dream, and we all know it. Unless governments intervene to legally force the use of smaller vehicles, we won’t trade our “Executive Urban Assault Vehicles” to sit in a minicar capable of reaching only 60 miles an hour with a following wind!
On my daily commute to work, I pass Farnborough Airport. This is the home to many ecologically-unfriendly executive private jet aircraft. The main A road that passes adjacent to it has recently had a new 50 mph speed limit imposed upon it, reduced from its previous 70 mph limit.
It seems that the local council are keen to reduce emissions in the local area!
Regardless of this, vehicles still charge past me doing well excess of the new limit, and the police don’t seem to be enforcing the new limit.
Maybe we should drive less distances? Maybe we should alter our fundamental mind set to become more locally focused, and adopty a new philosophy of not commuting longer distances?
I don’t think human nature is going to fix this particular problem.
It appears that the main thrust of the ecological argument is to initiate a societal shift from driving hydro-carbon powered vehicles to electrically powered cars.
However, this only addresses a part of the problem. Even if there is a global adoption of battery driven vehicles, the problems associated with the pneumatic tyre remain.
Until we have mastered an alternative to the conventional tyre we are still in trouble.
The auto industry faces a parallel challenge. What do we use as an alternative to the conventional vehicle tyre?
Answers on a postcard please…
 Friends of the Earth Report “Reducing Household Contributions to Marine Plastic Pollution 11/2018