Are diesels really bad for you?

diesel smoke
smoke is hazardous to other road users! Image:
Golf GTI

Similar performance and specification………………………………………

Golf GTD

……………………………but the red Golf GTD  puts out ten times more damaging emissions than the white GTI!











Even before Volkswagengate, there were rumblings that diesel emissions were hazardous; the emergence of Volkswagens misdeeds blew these up into a high-profile issue on which every journalist worthy of his or her salt has felt the need to opinionate.

And therein lies the problem: emissions is an incredibly complex subject, so the average journalist, and indeed most motoring hacks, simply seize on the soundbites they think they understand, and proceed to ‘educate’ their customers with what has often been just plain wrong information.

Cards on the table here. Despite a lifetime working in vehicle design and development, much of it helping to ensure that vehicles meet, and at times struggle to meet, their appropriate emissions standards, I do not pretend to be an expert on emissions by any means. It’s been clear to me, though, that one thing which has been lacking throughout the dieselgate saga are facts on which we can all draw sensible conclusions.

This has left the gate open for opinions to be aired as pseudo-facts – whether right or wrong. So we have heard pundits telling us, for example, that petrol cars are just as bad as diesel, that the emissions involved in making cars outweighs the pollution they create in their lifetime, and that electric cars are just as polluting as anything else because of the emissions generated in making the electricity for them.

So how on earth does the man in the street make sense of all the claims and counterclaims? What has been missing is an unbiased analysis of all the factors involved in the whole car emissions issue – a major task!

At last, however, we have to thank the website ‘Next Green Car’ for tackling this challenge and publishing data to identify the emissions generated in both making and using our cars, as well as the fuel to go in them, in a variety of real-world conditions, as opposed to sterile EU-style laboratory tests.

Next Green Car Ltd is an independent company developing data and digital solutions in the automotive sector. Whilst some of their analysis inevitably involves estimations, these appear to be backed by science, and their reports are certainly much closer to giving us a true emissions picture than anything which has been seen before.

Their emissions calculator, which can be found at is easy to use. Simply by entering a few details, you can discover the emissions generated by your car both in manufacture, and in use under various conditions, and compare them with others. The results might surprise you……………

We looked at two cars from the Volkswagen brand, identical except for the fuel they used. They were the petrol Golf GTI, and its stablemate the Golf GTD, virtually identical in specification & performance, except that one runs on petrol and the other on diesel. And before you ask – yes, the diesel Golf is Euro 6 and so not affected by any of the infamous ‘defeat device’ issues!

Under normal driving conditions over a typical 10,000 mile annual distance, the results show that, using the ‘official’ EU Test data, the petrol Golf creates out 3.08kg of NOx & PM, whilst the diesel model is almost identical, at 3.09kg. However, using real-world data, the petrol Golf emits a slightly increased 3.63 kg of NOx and particulate emissions compared to a staggering 8.3kg for the diesel model – almost 2½ times as much!

These figures factor in the emissions produced by making both the car & fuel as well as the all-important ones coming out of the exhaust pipe when driving. If you look only at the emissions produced when driving, the results are even more shocking. The petrol car produces only 0.58kg of NOx & particulates over 10,000 miles, whilst the diesel belches out 5.93kg – ten times as much!

Given that medical opinion seems unanimous that NOx and particulates emissions are seriously hazardous to health, Next Green Car have done a great job in putting some facts and numbers to the ongoing saga of petrol versus diesel.

Interested? – find out more here:-


1 Comment on "Are diesels really bad for you?"

  1. I guess the question doesn’t even arise. Diesel cars… AND hybrid cars are both nocive. Why ? Diesel cars are performant but use a huge amount of energy, which causes emissions, as we know. However, components of hybrid cars are also dangerous (i.e lithium batteries) and while driving, magnetic fields are produced.
    Let’s be careful…

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