Can diesel engines CLEAN urban air?

Can diesel engines CLEAN urban air?

A new report into the particulate emissions of non-exhaust sources such as tyres has reached a rather shocking conclusion. One of the findings is that a modern diesel engine can actually CLEAN the air it’s driving through. 

This is highly contradictory to some of the negative talk around diesel cars. The Emissions Analytics report opens the diesel discussion, saying “the truth is that they have emitted very few particles, at least in relative terms, since the broad introduction of diesel particulate filters a decade ago”.

“Filters are in fact so good, that in certain circumstances, when the ambient air is already polluted, a diesel car will tend to extract more particles from the air than it emits”.

Cleaning the air with diesel engines: nonsense?'make or break' for diesel in 2020

To test the theory, it worked with Auto Motor und Sport using four recent diesel models. Going to the extreme, they opened canisters of high intensity particles in front of the air intake on the cars as they idled for an hour. Particle concentration at the front soared from the 11,000 cm3 or-so ambient, to over 100,000 cm3. 

In contrast, the particle concentration measured at the rear, near the exhaust, remained flat, even dropping to around 10,000 cm3 towards the end.

Diesel use down for the first time in a decade

Then they moved to more realistic on-road testing for the four vehicles. Exhaust particles were measured from cold, neutral warm idle, under heavy load, and during DPF regeneration.

As best as possible, the typical operating conditions of a car day-to-day were simulated. Long distance, middle distance and short drives, with a mixture of cold and warm engine states, idling, heavy loads, regeneration conditions, etc.

The results were as follows:

  • Idle: 10,246 cm3
  • Warm engine: 15,803 cm3
  • Cold start: 9,114 cm3
  • Heavy load: 16,894 cm3
  • Filter regeneration: 155,555 cm3

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The standout result that Emissions Analytics cites, which it says it didn’t expect, is that the net addition of the car’s pollution is mostly dependent on the ambient air pollution. This reflects the way the car breathes air in, as well as the way it exhausts waste.

The overall results are staggering, with just two out of the six conditions showing emissions from the car being dirtier than the air the car is driving through. These were long distance and middle distance, in ‘clean air’ with an ambient of 10,000 cm3.

The ‘dirty air’ baseline was around 50,000 cm3. Over long distances, the cars removed around 27,984 cm3 from the dirty air. Over middle distances, they removed around 8,025 cm3 from the dirty air. On short drives, they removed around 40,886 cm3 from the dirty air.

Diesel car fuel filler

Even in clean air, as above at 10,000 cm3, a short drive removed 886 cm3 from the ambient air. Long distance and middle distance did, however, add 2,000 cm3 and 21,000 cm3 respectively.

Emissions Analytics clarifies, that it would be a broad stroke to say that diesel engines clean the air. This is purely a measurement of particulates, and ignores nitrogen oxides and other gaseous emissions. 

It’s also worth considering that many diesels still on the road are pre-DPF models. The results, nonetheless, remain food for thought.

One in 19 urban deaths linked to air pollution

deaths linked to toxic air pollution cities

A new study estimates that more than one in every 19 deaths in UK cities is related to air pollution. That makes  air pollution 25 times more deadly than road traffic incidents, in terms of the numbers killed.

The Cities Outlook study, conducted annually by Centre for Cities, refers specifically to urban areas, where the levels of PM2.5 particulates are mostly well above World Health Organisation guidelines. At present, these are not illegal levels in England, Wales and Northern Ireland.

Overall, 62 percent of roads that are monitored in UK cities exceed WHO guidelines for PM2.5. And 19 of the UK’s city road networks breach those guidelines entirely. That means all city streets are above safe pollution levels – an issue that affects 14 million people across Britain.

‘Transport is a significant, but not sole contributor’

deaths linked to toxic air pollution cities

Centre for cities, while highlighting the issue around transport emissions, cited other causes for high levels in cities. Fuel burning, such as in wood burning stoves and coal fires, is claimed to account for half of PM2.5 particulates in urban areas. Not all is locally generated either, as the south of England (a problem area) suffers with emissions blown in from Europe.


Cities with the most and least estimated PM2.5-related deaths
Most deaths Least deaths
Rank City PM2.5-related deaths, of total deaths Rank City PM2.5-related deaths, of total deaths
1 London 6.4% 1 Aberdeen 3.0%
2 Slough 6.4% 2 Dundee 3.1%
3 Chatham 6.3% 3 Glasgow 3.4%
4 Luton 6.2% 4 Blackpool 3.5%
5 Portsmouth 5.9% 5 Edinburgh 3.7%
Deaths in people aged 25 and over, 2017

‘Extra money and stricter guidelines’ 

“More than half of people in the UK live in cities and large towns,” said Andrew Carter, chief executive of Centre for Cities.

“Cities Outlook 2020 shows that they are having a damaging effect on their health, with air pollution killing thousands of people living in cities every year.

deaths linked to toxic air pollution cities

“Cities should be at the centre of the fight against toxic air and councils should take the steps needed, including charging people to drive in city centres and banning wood burning stoves.

“To help the Government needs to provide extra money and introduce stricter guidelines. The deadly levels of polluted air we’re breathing are legal across most of the UK. This needs to change. Failure to act now will lead to more deaths.”

Brake dust as toxic as diesel fumes, warn scientists

Brake dust emissions as bad as diesel

New research has revealed more about the dangers of particulate emissions from car braking systems. Tests indicate that brake dust could be just as toxic as particulates from the exhausts of diesel engines. 

Brake pad particulates were found to harm respiratory health, damaging lung cells when they enter. 

The study involved exposing macrophages (immune cells in the lungs that protect them from bacteria) to various particulates. Both diesel exhaust and brake dust particulates were found to reduce the ability of these cells to work. Both also caused the cells to produce immune signalling molecules, which inflame and damage lung tissue.

Brake dust emissions as bad as diesel

“At this time the focus on diesel exhaust emissions is completely justified by the scientific literature,” said Dr Ian Mudway, who led the research at the MRC Centre for Environment and Health at King’s College, London.

“But we should not forget, or discount, the importance of other components, such as metals from mechanical abrasion, especially from brakes.

“There is no such thing as a zero-emission vehicle, and as regulations to reduced exhaust emissions kick in, the contribution from these sources are likely to become more significant.”

Brake dust emissions as bad as diesel

The slice of the particulate pie that non-exhaust emissions represent is projected to increase. The current 7.4 percent figure is expected to rise to 10 percent by 2030.

This is in part due to the increasing weight of cars, which increases wear on brakes. Electric cars are also particularly heavy, and thus pose a greater problem in this regard.

How much have congestion zones improved air quality?

Emissions reduction congestion charge zone

In February 2020, it will be 17 years since the Congestion Charge was introduced for central London. Since then, the idea of incentivising uptake of cleaner cars has evolved.

The Ultra Low Emissions Zone (ULEZ) now operates in London 24 hours a day and 365 days a year. On top of that, 20 other UK cities are now considering similar schemes to the Congestion Charge. But how has air quality evolved over the past 17 years?

Select Car Leasing has analysed air quality data collected from three points within the zone, before and after the charge was brought in. Overall, carbon monoxide levels are 60 percent lower now than they were before the charge. Likewise, nitrogen dioxide is down by 24 percent, while suphur dioxide is down 61 percent. 

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“Our data shows that the London Congestion Charge zone has broadly achieved its aims,” the report concludes.

“Many Londoners will believe that the cost of cleaner air is certainly a price worth paying. It could be down to this success that many other congestion charges and toll roads are planned throughout the UK in the near future.”

Where are similar schemes being considered?Traffic in Bristol

There are 20 further zones being considered across the United Kingdom. Glasgow, York and Leeds are confirmed to be following London. 

Cities where schemes have been proposed include Newcastle upon Tyne, Manchester, Warrington, Birmingham, Sheffield, Oxford, Bristol, and Bath. Bristol has all but confirmed an outright ban of diesel-powered private cars in certain parts of its city centre. Edinburgh, Dundee and Aberdeen have proposals to follow in Glasgow’s footsteps for Scotland.

As for where could jump on the ULEZ bandwagon? Derby, Cambridge, Cardiff, Slough, Reading and Fareham are all possibles, according to Select Car Leasing.

Tesla battery life loss

The hope is these zones will encourage drivers to sell their petrol- and diesel-powered cars, and buy EVs. That means eventually, a great deal of cars paying minimal road and fuel taxes. At present, these represent a £28.8 billion revenue stream. 

Select Car Leasing suggests three possible options: taxing electric cars more heavily, putting duty on electricity and introducing more tolls. Whatever happens, the government will have to raise the funds sooner or later.

Electric car uptake ‘not enough in isolation’ to improve air quality

Electric cars not enough to improve air quality in isolation

New research from the British Heart Foundation (BHF) has led to the conclusion that those who live in the most polluted urban environments could be losing seven months off their lifespan. Breathing the worst-polluted urban air is, according to BHF, equivalent to smoking 150 cigarettes a year. The situation is such that some don’t think that our transition to electric cars is going to be enough.

This, according to Mathew Hassell, founder and CEO of some of the UK’s largest transport management businesses, including Transport2, and Kura.

“The news that the toxic air in our cities is now actively shortening our lifespan is worrying but hardly surprising,” Hassell said.  

Electric cars not enough to improve air quality in isolation

“Given that 33 percent of the toxic emissions we produce come from transport, it is here where a revolution is needed – and quickly.”

By revolution, Hassell is looking beyond each of us swapping in our petrol and diesel cars for EVs. The amount of cars overall is a problem, whatever they’re powered by, he says.

“While greater uptake of electric vehicles is seen as the solution by many, this isn’t enough in isolation. We must do more to get cars off the road, meaning that investment in areas such as Mobility as a Service (MaaS) and shared transport will be the more sustainable, viable solution to creating a greener future.”

He also highlights specific problem scenarios where pollution spikes, citing the school run. One in four cars on the road during rush hour are linked to the school run. Hassell thinks that investment in school transport would have a large impact. This to an end of getting cars off the road as above, and therefore lowering emissions markedly. The impact he says, could “rival or even exceed that of EVs”.

‘There is no safe level of air pollution‘Electric cars not enough to improve air quality in isolation

Prior to parliament being dissolved for the general election, the government introduced the Environment Bill. Among other things, it committed to emissions targets, though these weren’t as strict as those recommended by the World Health Organisation. 

The British Heart Foundation says that 11,000 coronary heart disease and stroke deaths can be attributed to air pollution every year. Jacob West, executive director of healthcare innovation at the BHF, calls air pollution a “major public health emergency” that has ”not been treated with the seriousness it deserves” and that “we will look back on this period of inaction with shame”.

Dr Mark Miller, contributing BHF researcher, said “there is no safe level of air pollution. The potential health benefits of realising these [Environment Bill] targets are enormous, allowing everyone to live healthier lives for longer”.

Sales of SUVs ‘making a mockery’ of emission policies

SUV emissions outweigh EV benefits

In spite of the growing popularity of electric cars, a new study suggests the sales of large, heavy, emissions-intensive SUVs is far outweighing any initial benefits. On average, SUVs emit around 25 percent more CO2 than normal cars.

SUVs and crossovers outsell electric cars 37 to one. While electric cars are increasing in popularity, with registrations doubling, the SUV craze is stronger still. They made up 21.2 percent of car sales last year.

Contrast to 2017, when SUVs made up just 13.5 percent of car sales. A decade ago, when the crossover was just getting traction, SUV sales were 6.6 percent. 

SUV emissions outweigh EV benefits

Between 2015 and 2018, 47,400 electric cars were sold. By comparison, near-on 1.8 million SUVs were sold in the same period. The study noted that affordable finance deals make SUVs more attractive to car buyers. 

Applying the average increased emissions from SUVs to that figure, 1.8 million SUVs have emissions equivalent to 2.25 million normal cars. That’s an extra 450,000+ cars’ worth of emissions, outweighing the sales of electric cars almost ten-fold. 

CO2 emissions had been reducing since the early 2000s, but rose in 2016. The Department for Transport has admitted this could be “broadly due to a shift towards registering larger cars, which have higher emissions”.

SUV emissions outweigh EV benefits

“The rapid uptake of unnecessarily large and energy-consuming vehicles makes a mockery of UK policy efforts towards the ‘road to zero’,” said Professor Jillian Anable, co-director of the UK Energy Research Centre.

“In effect, we have been sleep-walking into the issue. The decarbonisation of the passenger car market can no longer rely on a distant target to stop the sales of conventional engines. We must start to phase out the most polluting vehicles immediately.”

California will no longer buy gasoline-only cars

California will no longer buy petrol-only cars

The State of California will no longer buy vehicles solely powered by internal combustion engines, says the California Department of General Services (DGS).

State agencies will also avoid buying vehicles from a company that doesn’t adhere to California’s upcoming strict new rules on fuel economy. 

The specifics don’t mean that California is necessarily going all-electric. Looking in finer detail, ‘solely-powered’ basically means conventional non-hybrid automobiles. So-called ‘electrified’ gasoline cars, such as plug-ins and hybrids, will still be allowed.

Exceptions will also be made for some public safety vehicles – where suitable electrified alternatives aren’t available for the specific use case.

California will no longer buy petrol-only cars

The ‘no non-hybrids’ rule is effective now. As for compliance with the California Air Resources Board (CARB) rules, that will come in on January 1, 2020.

California has its own standards for fuel economy, that are more strict by comparison with the rest of the United States. Only Ford, Honda, Volkswagen and BMW are on board with these fleet-average standards, over and above the more relaxed national rules.

California’s fleet rules: money to gainCalifornia will no longer buy petrol-only cars

It’s estimated that around $74 million was spent on fleet purchases in 2018 by the state of California. Of that, ‘non-compliant’ marques like Chevrolet, Fiat-Chrysler and Toyota made up over $40 million.

Even though all of these marques will have low and zero-emission / fuel consumption vehicles under their umbrellas, they won’t be part of the Californian new car fleet next year. Why? Because they’ve chosen to follow nationwide standards, not California’s – a move for which all have been criticised.

Compliant Ford, meanwhile, made up $18 million of that California state spend. It could stand to win big, as a vacuum of sorts opens for 2020 and beyond.

Indeed, could the state of California be the first big buyer of the new all-electric Ford Mustang Mach-E? It looks possible.

In 2018, the Californian fleet had a six percent figure for fleet BEVs and plug-in hybrids. Big changes are to come, then – and fast… 

Should SUVs be banned from company car fleets to cut CO2?

Should SUVs be banned from company car fleets

A new report reveals the rise in popularity of SUVs as one of the largest contributors to increases in CO2 emissions around the world. Now, the appropriateness of these vehicles for business fleets is being questioned.

High-riding cars, from hatchback-based ‘soft-roaders’ to luxury SUVs, have increased in popularity enormously over the last decade or so. Where once their UK market share was 17 percent, it now stands at 39 percent.

SUVs tend to be bigger, heavier, less aerodynamic and therefore less efficient than normal cars. Crucially, on average, they’re more polluting. So says an International Energy Agency document, which has highlighted the issue.

Should SUVs be banned from company fleets?

Should SUVs be banned from company car fleets

“The statistics in this new report are pretty shocking and should at least prompt businesses to check, as far as possible, the real-world emissions performance of not just fleet SUVs that they operate but any which are used through affinity leasing and grey fleet,” said Peter Golding, managing director of FleetCheck.

“There is certainly a need, the numbers suggest, to ascertain whether SUVs that are being operated on company business comply to sensible CSR requirements and even perhaps asking whether they are projecting the right image for your business.”

In spite of the figures, an outright ban isn’t being suggested. Rather, businesses are being advised to decide whether high-emitters “should have a place as company transport”.

Should SUVs be banned from company car fleets

“Of course, this should not mean automatically removing every SUV from your fleet,” Golding continued.

“Some have emissions figures that are broadly comparable to equivalent cars. However, others certainly don’t, even among models that appear to be among the softest of soft-roaders.

“Businesses need to decide, at a corporate level, whether it is right that vehicles of this type should have a place as company transport and look at whether their policies need to be amended to take account of their findings.”

Diesel cars preferable to petrol SUVS

Should SUVs be banned from company car fleets

Golding continues, referencing the ‘Dieselgate’ scandal that tarred the image of diesel fuel in the eyes of consumers. While noting the severity of the diesel emissions issue, he said “it makes almost no sense that diesel cars are often giving way as everyday transport to petrol SUVs”. 

While better on nitrous oxide (NOx) emissions generally, CO2 figures rise drastically by comparison in petrol SUVs, as does fuel consumption.

Plug-in hybrids aren’t the answer

Should SUVs be banned from company car fleets

Golding criticises plug-in and ‘self-charging’ hybrid SUVs, too, saying the benefits of their electrified powertrains are felt only in specific circumstances. 

Short journeys are best, and only if they’re regularly charged in the case of PHEVs. On long motorway runs, “for higher mileage fleet drivers, they are generally poor choices”.

Porsche 718 Boxster S

Porsche vindicated? 718 Boxster S scores top ‘A’ rating for NOx emissions

Porsche 718 Boxster S
Porsche engineers may be breathing a clean-air sigh of relief as the results from the independent EQUA Index NOx tests show the new four-cylinder 718 Boxster S has achieved a best-possible A-rating for its low emissions.

It’s an excellent result for a sports car – although enthusiasts may still be questioning Porsche’s four-cylinder turbo move: the (admittedly much more expensive) Porsche 911 Carrera S Coupe was also given an A-rating for NOx emissions…

New EQUA ‘NCAP for NOx emissions’ test ranks real-world car pollution

Other new cars tested that gained the top A rating this month were the Ford Focus RS and Audi TT 1.8 TFSI Sport; indeed, nine of the 10 petrol cars tested this month scored the top A rating.

In contrast, the best-ranked diesel models tested only scored a C-rating; they were the BMW 320d ED, Volkswagen CC 2.0 TDI and Skoda Superb 1.6 TDI. Other diesels performed worse still.

This, says Emissions Analytics – the organisation behind the EQUA Index testing regime – proves that petrol-powered sports cars are capable of lower NOx emissions than regular diesel-powered saloon cars.

A C-rated car meets the Euro 5 limit for diesels, rather than the current Euro 6 standard, and is similar to the generous 2.1 conformity factor for Euro 6 diesels under the forthcoming new European ‘real world’ drive cycle tests.

An A-rated car, in contrast, meets Euro 6 emissions with ease; NOx emissions are almost non-existent. Whether enthusiasts consider that enough to justify a four-cylinder turbo Porsche is another matter…

2.0-litre TDI engine

Volkswagen yet to fix ANY emissions scandal cars in Britain claims minister

2.0-litre TDI engineVolkswagen has not yet fixed any British cars involved in the emissions scandal, a junior minister at the Department for Transport has told the Transport Select Committee.

“They haven’t fixed any cars yet, I’m disappointed to announce,” Robert Goodwill MP said. “And they will need to have their fix approved by us before they do it.”

The news, reports Reuters, contrasts with Volkswagen’s confirmation last week that a recall of 2,000 Amarok pick-ups had begun in January, and that rectification for some Audi and SEAT vehicles is now underway.

Which? Executive director Richard Lloyd called it “outrageous” that UK consumers are still being left in the dark on the VW scandal – and the organisation is calling upon the government to take immediate and urgent action.

“It is completely unacceptable that 7 months after this was first reported, following further testing and investigations, VW’s customers still remain in the dark on what the fix will be, what the impact will be on their car, and therefore whether they are entitled to compensation.”

Volkswagen’s decision to offer compensation to U.S. owners but not UK ones was also criticised. “Separate to the legal debate about compensation claims, people simply cannot understand why VW have offered US consumers a goodwill payment whilst refusing to provide this for their UK customers affected by the very same issue.

“VW seem to have put UK consumers at the back of the queue.

“The U.S. government has acted quickly to hold VW to account. In the UK progress to date has been woefully slow. The transport secretary must now intervene and stand up for UK consumers.”

Goodwill told the Transport Select Committee that the Serious Fraud Office is looking into the issue of compensation for UK Volkswagen Group vehicle owners.