Share |

Monday 26 January 2015

Review: 'The Great Car Con', Channel 4 Dispatches

Channel 4’s Dispatches has produced much penetrating investigative journalism over the years, and this evening’s episode confirmed what I have suspected for many years: diesel is neither good for human health nor the environment, but actually bad for both. A lungful of diesel is deeply unpleasant, as any regular cyclist or runner will attest, so it came as no surprise to learn that the particulates belched out by diesel vehicles make the emissions from their petrol-driven equivalents appear as fresh air by comparison. Still, it was sobering to learn that a diesel engine will produce 22 times as many particulates as a petrol one, as well as four times as much nitrogen dioxide. Whereas these particulates have proven links with an increased occurrence of asthma, the nitrogen dioxide poisons the blood, causing stroke, heart disease and diabetes, resulting in an estimated 29,000 additional premature deaths across the UK each year. Professor Roy Harrison of the University of Birmingham has been warning ministers of the dangers of diesel pollution for over 20 years, but he has been ignored.

These figures constitute serious cause for concern, and measurements have shown that nitrogen dioxide pollution significantly exceeds safety levels on the streets of a number of our cities. In London, Birmingham and Leeds, it is estimated that it will take at least fifteen years for its concentration to meet EU safety levels (something positive introduced by the EU in this instance). There is too much nitrogen dioxide in 38 out of 40 areas in the UK.  

Last year the sale of diesel cars outstripped the sale of petrol-driven models in the UK, with 10 million drivers now having diesel vehicles. They were incentivised, following Kyoto, as a means of reducing carbon dioxide emissions, with lower car tax and claims of far greater fuel economy compared to those run on petrol. A further surprise revealed by Dispatches, was the extent to which motor manufacturers significantly doctor their emissions data and claims for fuel efficiency, with the miles per gallon being on average 22% less than what manufacturers claim when taking into account data gathered from 550 models of car; in only eight of these instances were the cars found to be as fuel efficient as claimed.  

Some politicians have now awakened to the reality of diesel vehicles and the dangers that they pose to public health. Boris Johnson, for example, wishes to introduce an Ultra Low Emission Zone in London, charging drivers of diesel vehicles even more to enter the city’s Congestion Charge Zone. Although the Government received a detailed report on the health impacts of diesel vehicles in 2010, it has not acted upon its findings, so the purchase and use of diesel cars remains incentivised. Could all this be about to change? What then, asked Dispatches, for the second-hand market in diesel vehicles? Could it be time to sell? Will we witness a move away from diesel as a preferred fuel in years to come? 

Alas, although the fuel efficiency of modern cars is improving (despite the figures being doctored), the pace of technological change is proving stubbornly slow in bringing about a clean mass-transport revolution. The long-awaited goal of hydrogen-powered vehicles has yet to be achieved, so in the interim, we are at best stuck with the inefficient, and not necessarily ‘green’, technology of electric and hybrid vehicles. They are, without doubt, an ecological improvement on what has gone before, but exclusively electric vehicles still have a short range, as well as large, heavy and cumbersome batteries, which in themselves constitute a new waste-disposal problem. Moreover, the electricity used for their recharging, more often than not is generated using fossil fuels. If nuclear fusion becomes truly viable one day, then electric vehicles – pending improvements to their range and efficiency – could be become genuinely viable and green. In the interim, the legislation privileging diesel as the fuel of choice for the motorist needs to be revisited and repealed, for the sake of improving public health, and the environment.


  1. Diesels can't be banned soon enough.
    You'll be happy to hear EV's are closer than you think. They are 35% cleaner even if charged entirely by coal powered generation (which never happens). Battery technology is advanced enough that soon one battery will last the life of a car. The technology already exists to charge, store and transfer to your vehicle from solar power alone.
    Mass market EV's will be upon us in 3 years with enough range and fast charging for those long journeys. 90% of all journeys will only ever require home charging.

    1. It'll be interesting to see how this market develops. If the problem of the limited range of electric vehicles can be adequately addressed, then they could serve as a useful stop-gap technology until, and if, hydrogen fuel cells, or some other form of cleaner technology are developed. If the long dreamt of goal of creating and harnessing nuclear fusion is achieved, then they could be a good option.

  2. "as well as four times as much nitrogen dioxide"

    That might be an underestimate. If the figures on Toyota's website (the only manufacturer I can see that to list any NOx emissions) are to be believed, the problem could be bigger than that.
    In the Yaris range, the 1.5 hybrid puts out 6 milligrams of NOx per kilometre.
    The 1.33 petrol with an auto 'box puts out 7.2mg/km and its manual sibling comes in a little higher at 8mg/km.
    The 1.0 petrol fares worse at 14.8mg/km.
    However, the 1.4 diesel is another league though, at a barely credible 141.1mg/km.
    (click 'Specification', then 'Exhaust Emissions')

  3. So-called 'modern' Euro 5 diesel cars emit in average 560 mg/km NOx. Any figures in catalogues are not real-world figures but data collected under very artificial driving conditions (NECD) .. so not of this world!

    1. Motor manufacturers, like politicians, would seem to be highly adept at spin.


Comments that call for or threaten violence will not be published. Anyone is entitled to criticise the arguments presented here, or to highlight what they believe to be factual error(s); ad hominem attacks do not constitute comment or debate. Although at times others' points of view may be exasperating, please attempt to be civil in your responses. If you wish to communicate with me confidentially, please preface your comment with "Not for publication". This is why all comments are moderated.