Comment: Diesel cars are not the enemy

Published 29 December 2014

Diesel cars came under fire this year following research that shows pollution levels are increasing.

Diesel engine emissions contain particulate matter and oxides of nitrogen (NOx), both of which have harmful effects on health, and the latter particularly for people who already have respiratory problems such as asthma.

Petrol engines, although producing higher levels of CO2, have a tiny amount of particulate and NOx emissions by comparison with diesel engines.

Even the latest set of Europe-wide emissions rules have different thresholds for NOx applied to petrol and diesel engines because of the challenge of reducing those emissions in diesel. The limits for particulate matter and petrol engines only apply to those with direct injection.

But diesel emissions are much ‘cleaner’ than they were a decade ago. Even five years ago. The permitted maximum level of NOx emissions for diesel engines under Euro 6 emissions riles that came in during 2014, is less than half that allowed under Euro 5, which came into force in 2009.

It is almost universally accepted that emissions of greenhouse gases are bad for the health of the planet and have an impact on the global climate. Unless they are reduced it would most likely lead to dramatic and irreversible changes to ecosystems that we rely on for producing the oxygen we need to live.

And this has led us to where we are today: diesel cars with typically lower CO2 emissions than petrol equivalents have been indirectly incentivised for more than a decade. Choose a diesel car and the lower CO2 emissions generally result in lower road tax, lower fuel consumption, stronger residual values, lower company car tax, and lower employers’ national insurance contributions.

As well as being the favoured fuel of most company car fleets, diesel also has strong appeal for some retail customers, with diesel models taking around 50 per cent of total new car registrations.

But air quality is now reaching a critical point according to a report by MPs. The Environmental Audit Committee now says we are on the verge of a public health crisis thanks to air pollution.

London Mayor Boris Johnson has also proposed penalising all but the cleanest diesel vehicles in a new ultra-low emission zone mooted for 2020. There is also suggestion of a scrappage scheme for diesel cars.

Drivers of diesel cars, as well as facing higher penalties and taxes in future, could become a pariah in the media to the same extent that those driving big ‘gas guzzling’ 4x4s were a decade ago.

No one seems to be suggesting we target older vehicles that were designed to meet out of date rules on emissions, and over time have been poorly maintained and perhaps missed scheduled services. How many old diesel cars do we see producing clouds of thick smoke behind them.

I haven’t heard of any proposals to get old taxis and black cabs off the roads, nor older buses, vans and trucks.

Is it the case that the truck, LCV and taxi industries have powerful lobbies supporting them, that can mobilise and campaign on issues that could add more cost to their businesses?

And if there were a scrappage incentive to trade in a diesel car for a new model, while the new car market is relatively healthy, it would have a disastrous effect on resale values of all cars three or four years down the line.

Today’s diesel cars are the cleanest they have ever been, and thanks to hi-tech equipment on board that cleans up exhaust gases as we drive, the exhaust gases are almost as clean as for petrol cars, and have lower CO2 emissions.

Road freight uses diesel. A lot of it. If we had to stop using diesel tomorrow, there would be no food in the shops. Many of our trains still use diesel. No doubt allowances will be made for services seen as 'essential', but diesel car drivers are in danger of being targeted unfairly - especially those in a new diesel company car.

They have no association to speak specifically for them and over the years, like all motorists, have been so used to being over-taxed through high fuel duty and increasing VAT that they will just accept any further change that penalises them. It’s time for them to make themselves heard before it’s too late.


Klockner    on 29 December 2014

Why is it car manufactures seem quite on this subject. Could it be they see the future in smaller powerful petrol engines and hybrids.

Tancred    on 29 December 2014

The government is full of daft ideas and this is simply the latest in a very long list. Keeping the 70mph motorway limit is another piece of lunacy. Without the economy offered by diesel everything would go up in price as transport costs would increase, and, besides, diesel drivers already pay more at the pump than petrol users - on the continent it tends to be the other way round. Why penalise a more cost effective fuel? Until electric cars become truly viable, which won't happen for many years, diesel will remain the most economical way of fuelling a vehicle.

Add a comment


Value my car