Diesel fuel gauge on car dashboard

Diesel and air pollution: 10 facts about an invisible killer

On 18 September 2015, the Volkswagen scandal  propelled air pollution into the public consciousness.
  Published:  18 Sep 2017    |      4 minute read

Dodgy software enabled VW cars to pass emissions tests despite producing up to 40 times the legal limit of deadly pollution.

But although it was caught red-handed VW has faced no punishment in the UK. In fact, its business is soaring, posting record €4.4bn worldwide profits for the first quarter of 2017 alone.

VW logo on bumper

At the same time, evidence of diesel’s danger to human health has strengthened and people continue to suffer, not helped by the government recently ducking its legal and moral responsibility to sort out our diesel pollution problem.

Many in the car industry seem determined to peddle the line that old diesel cars were polluting but new ones are, essentially, fine.

Unfortunately, that’s just not true.

So here are 10 facts that show the depth of the problem with diesel and why Friends of the Earth is campaigning for a total phase out of the fuel source in all road transport by 2025.

1. Diesel exhaust causes cancer…

According to the World Health Organisation (WHO), diesel is a Group 1 carcinogen, meaning that it causes cancer in humans. That’s the same class as tobacco and mustard gas.

2. …and all manner of other health problems

Nitrogen Oxides (NOx) and small particles known as Particulate Matter (PMs) – both prevalent in diesel fumes – combine to contribute to up to 36,000 premature deaths a year in the UK. That’s more than tobacco or obesity.

The tiny ‘PM2.5’ particles released by diesel vehicles are so small that they can travel deep into the lungs, aggravating breathing problems such as asthma, and lead to worsening of heart and lung diseases.

According to Dr Jonathan Grigg, from Doctors Against Diesel:

“If you’re going to design something that would effectively deliver a toxic substance into the lungs, you couldn’t do better than the diesel soot particle.”

3. Diesel causes climate change

Much though car companies would like you to think diesel is the ‘green’ alternative to petrol, there’s no getting away from the fact that burning diesel produces greenhouse gases and worsens global warming. There are also serious questions about the extent to which diesel produces less carbon than petrol when burned, as has long been claimed.

cars in heavy traffic

4. Diesel cars cause most of the problem

Industry lobbyists complain that diesel cars are singled out unfairly given the relatively small proportion of the UK’s total NOx pollution for which they are responsible. It’s a flawed argument.

What matters is where NOx pollution does the most damage to people, i.e. where it can quickly enter our lungs before it disperses in the atmosphere.

For instance, NOx emitted from a diesel car’s exhaust pipe at buggy level, in a crowded city, is far more harmful than NOx billowing out of a 100m chimney in the middle of the countryside.

Or as a colleague pithily put it, “most darts are thrown at dart boards. It's the ones thrown at people's heads we'd like to get rid of.”

The government's latest analysis found that:

"road transport is responsible for some 80% of NOx concentrations at roadside, with diesel vehicles the largest source in these local areas of greatest concern."

5. Diesel cars are 10 times as polluting as petrol cars

Diesel cars emit around ten times as much NOx as their petrol equivalents according to the organisation Transport and Environment. Even the latest so-called ‘Euro 6’ diesel cars emit five times the NOx of comparable petrol cars – as noted by Policy Exchange (see page 11 of their report).

6. Pollution filters are routinely removed from diesel cars – and it’s legal

Modern diesels are fitted with a Diesel Particulate Filter (DPF) to trap dangerous soot particles before they leave the exhaust pipe. But irresponsible garages offer to remove these filters for just a few hundred pounds, in order to make the cars more enjoyable to drive.

Friends of the Earth won a campaign to ban advertising for this service, but the practice still appears rife, meaning many diesels are polluting far more than they were when they were manufactured.

7. The diesel testing regime is still broken

As of September 2017, all new diesels have to pass ‘Real Driving Emissions’ tests, designed to better replicate normal driving conditions than the old, flawed, lab tests that facilitated the VW scandal. But investigations indicate that this new regime fails to pick up the extent to which diesels’ emissions remain dangerously high in real world conditions like rush hour.

8. There are around 12 million diesel cars on UK roads

The number of diesel cars in the UK has gone up from 1.6 million – or 7% of the fleet in 1994 – to around 12 million today. Diesel vehicles still represent 47% of new car sales in the UK, up from around 13% a decade ago, although sales are now falling as concerns grow about air pollution.

Even second hand diesels are dropping in value as drivers and dealerships alike rush to ditch diesel.

Male cyclist wearing helmet in street putting on anti-pollution mask .

9. Electric cars are now a viable alternative to diesel

In the past four years, there has been a 26-fold increase in registration of electric cars in the UK. Electric cars are almost as cheap to own as petrol cars, and the latest models have a range of several hundred miles.

As our blog on electric vehicles shows, they are now a viable alternative to diesel, alongside better public transport and cycling options.

10. You can measure the level of nitrogen dioxide, one of the pollutants pumped out by diesels, where you are

We’ve developed a Clean Air Kit that allows you to find out about air pollution where you live. Thousands have already ordered theirs and joined the national movement to ensure everyone, wherever they live, can breathe clean air. And you can too.

Clean air kit unpacked, showing contents.
Clean air kit unboxed
Credit: Callum Burns

And you can help us ditch diesel. We're calling on the government to completely end all diesel use on our roads by 2025.