Earlier this month London mayor Boris Johnson’s environment adviser told the London Assembly Environment Committee that the introduction of an ultra-low emission zone in London by 2020 will give vehicle manufacturers a “hefty shove” to improve emission standards. The proposal, first put forward by the mayor in February, would “help the automotive industry to wake up and stimulate growth”, Matthew Pencharz added. “These measures can actually help drive the market – the automotive industry can start producing cars that you will be able to drive in central London after 2020.” The proposals currently on the table could potentially see the zone cover a similar area to the congestion charge zone and have only zero or low emission vehicles driving in central London during working hours after 2020.
Which all sounds very positive, in terms of reducing the air pollution associated with road transport.
But there’s a problem, because ‘emissions’ actually covers far more than what comes out of your exhaust pipe, so no matter how clean your engine is, there will still be pollution associated with driving. “Non-exhaust processes are an important source of particulate matter, constituting approximately 50% of PM10, 25% of PM2.5 and 90% of the coarse fraction (PM coarse) of road traffic emissions,” a TRL report for Defra explains. “The most important sources of vehicle non-exhaust emission were found to be tyre wear, brake wear and road surface wear.”
And unfortunately PM (particulate matter, to give it its full title) produced by tyre wear, for example, is rather nasty stuff.
Particulate matter from tyres, for example, is composed, amongst other things, of zinc, latex rubber, carbon black and polyaromatic hydrocarbons and studies have shown that tyre particulate chemicals are possibly carcinogenic, mutogenic and toxic to lung tissue. Some researchers have also linked airborne ultrafine tyre wear particles that are inhaled into the lungs to a rise in asthma in urban areas.
The scale of the problem should not be underestimated – some sources estimate that poor air quality is a factor in almost 30,000 premature deaths in the UK each year. This figure, if accurate, means that air pollution plays a part in nearly 5% of all annual UK deaths.
Clear engines are manifestly a good thing but even the age of the electric car (if it ever arrives), with zero tailpipe emissions, will not make the pollution problem go away completely. Regenerative braking will help by reducing brake wear. Improvements in tyre technology will also make a difference, of course.
But can anyone out there think of any other way in which this problem might be tackled, we ask?
Or is it really about time someone got around to inventing the hover car?