The predictable war on diesel cars is underway. The days of promoting them as ‘climate-friendly’ are over, in the UK at least. Diesel trucks, vans and buses are overlooked.
Brixton has since been overtaken by Knightsbridge as Britain’s most polluted district so far this year. The wealthy west London suburb has exceeded the EU nitrogen dioxide (NO2) limit for a total of 52 hours already this year, nearly three times the legal annual allowance of 18 hours, according to the latest figures from Dr Gary Fuller at King’s College London.
But traffic pollution is by no means confined to these London hotspots.
The nitrogen dioxide problem spreads across dozens of towns and cities in the UK, where it can bring on asthma and other respiratory problems and contributes to an estimated 12,000 early deaths each year.
Almost every region affected
Last year, almost every region of the UK – 38 out of 43 – had at least one area exceeding the legal EU limit for NO2 and in many regions there were numerous breaches. In those areas where NO2 exceed EU limits, diesel vehicles were overwhelmingly to blame, responsible for 80 per cent the nitrogen dioxide in the air. Most of the rest comes from trains, ships and industry.
“The NO2 problem is really a diesel vehicle problem. Even a fairly new diesel car would emit about five times as much nitrogen dioxide as a petrol car,” said Professor Martin Williams, of King’s College London.
Diesel engines have traditionally been used by large vehicles such as lorries, vans, taxis and buses because they are more powerful and durable than petrol motors. But they have also become increasingly common in private family cars after an environmentally-motivated government push at the start of the century on the basis that diesel engines produced far less carbon dioxide than petrol ones and would help curb climate change.
Unintended environmental consequence
Car-owners flocked to diesel motors in response to financial incentives such as reduced road tax. Diesel car ownership soared from 3.5 million in 2001 to more than 8 million now, as sales overtook petrol engines for the first time in 2010 and kept rising.
But an unintended consequence of rising diesel car ownership has been air pollution, with nitrogen dioxide levels in Britain the third highest in the EU, exceeded only by France and Germany.
Furthermore, petrol engines have become so much more efficient in recent years that they no longer produce that much more CO2 than diesel cars, says Prof Williams. “The climate change argument for diesel is getting much weaker, while the petrol argument is overwhelmingly in favour of petrol,” he said.