In an article originally published in The Conversation, Paul Niewenhuis Senior Lecturer and Co-Director of Cardiff University’s Electric Vehicle Centre of Excellence (EVCE) looks at the environmental credentials of diesel cars.
Diesel cars have recently become subject to considerable negative publicity thanks to the amount of toxic emissions they produce. Some governments are planning to discourage their use or even ban them from urban areas altogether. Yet some diesel car owners have reacted angrily, arguing they bought the vehicles because they were supposedly the environmentally friendly option.
The science now tells us that diesel vehicles cause more than four times the pollution than petrol cars.
Sadiq Khan, Mayor of London
Diesel was promoted as a more environmentally friendly fuel as part of the EU’s response to the 1997 Kyoto Protocol to reduce greenhouse gas emissions, especially carbon dioxide (CO₂). Diesel engines are “lean-burn”, meaning they use less fuel and more air to get the same performance as a petrol engine.
So, while diesel fuel contains slightly more carbon (2.68kg CO₂/litre) than petrol (2.31kg CO₂/litre), overall CO₂ emissions of a diesel car tend to be lower. In use, on average, this equates to around 200g CO₂/km for petrol and 120g CO₂/km for diesel.
But even when governments were promoting diesel cars, we knew there were issues with toxic emissions (those immediately harmful to humans, not CO₂). Heating air in an engine produces nitrogen oxides (NOₓ) which include the toxic nitrogen dioxide (NO₂), greenhouse gas nitrous oxide (N₂O) and nitric oxide (NO), which reacts with oxygen to form NO₂. In a petrol car, these can be cleaned up by a three-way catalytic converter so that it emits on average around 30% less NOₓ than a diesel car, without after-treatment.
We know that long-term exposure to nitric oxide can significantly increase the risk of respiratory problems, and so these emissions have been regulated for some time. The fine particulate matter (PM) that diesel engines produce also causes cancer and can have acute respiratory effects.
Particulate filters in car exhausts can reduce PM emissions by more than 90%, but they require good operating conditions and regular maintenance. They can also produce more nitrogen dioxide, making diesel one of the main sources of this toxic gas.
European Union, Author provided
For all the differences between petrol and diesel cars in the past, current EU emissions standards for new vehicles of both types are quite similar. But there are still many older cars on the road that conform to earlier emissions standards.
Plus, in order to achieve these standards, diesel engine manufacturers have had to resort to technologies such as particulate filters, which tend to clog up when used mainly for urban driving. And the latest emissions technology requires the owner to regularly add a urea mixture such as AdBlue to the engine. By contrast, petrol emissions systems regulate themselves, needing less driver input.
The problem is that governments often fail to grasp that focusing on one issue at a time, such as CO₂ output, inevitably leads them to ignore others, such as toxic emissions. It seems likely that to tackle both problems, governments will eventually have to start banning vehicles with internal combustion engines altogether, initially in urban areas and ultimately more generally.
Verdict
For most cars built over the past 20 years that may still be in use, petrol is likely to be less polluting overall than diesel. Petrol cars also require less maintenance to keep them performing at that level. But new, well maintained diesel cars, built to the latest standards have similar emissions to new petrol vehicles.
Review
Aonghus McNabola, associate professor in civil and structural engineering, Trinity College Dublin
Overall I find this a fair reflection on the topic of diesel cars. Some points are worth elaborating further. From a health impact point of view, the public should also be particularly concerned about the fine particulate matter emitted from diesel engines because it is associated with poor heart health. Research has proven that increases in background concentrations of particulate matter result in more hospital admissions and deaths from heart attacks, particularly among those already at risk.
The near EU-wide plan to encourage people to buy diesel vehicles in the past number of years is another example of the lack of connection between air pollution policy and climate change policy, and the difficulties of considering CO₂ emissions separately to the many other thousands of compounds that human activities emit. Replacing petrol cars with diesel ones does result in lower CO₂ emissions and climate impacts but it has clearly been worse for human health.
This article rightly sums up the outlook that new, well maintained diesel vehicles have quite similar levels of particulate emissions to petrol cars, although they are still higher. However, most vehicle fleets are dominated by the older and considerably more polluting, earlier emission standard vehicles. It will take many years for these vehicles to make their way out of operation. During this time, human health will continue to be damaged by diesel emissions.
This article was originally published on The Conversation. Read the original article here.
I drive 40 miles a day, and can always tell when I’m behind a diesel due to their smell similar to chlorine gas. I spend most of the journey with the air re-circulation on. It makes no difference how old or new the diesel vehicle is. This never happens with petrol cars, the odd one burns oil but they won’t last long like that so fairly quickly get removed from the road.
We’ve known for years that diesel fumes are dirty and bad for us, but the EU put CO2 (for so-called climate change) above the health of their subjects.
I look forward to ICE vehicles gradually being replaced by electric. I suspect this will put the price of electricity up due to decreasing fuel tax&duty. Electricity used to be 3x more than gas per kWh. Now it’s 4x-5x more. Maybe it’s time for some one to invent a natural gas powered car!
Have you considered the strain EV’s will put on the National grid? The NG is already overloaded as is.. imagine if everyone started plugging 80kWp battery’s in every night…
However, I do agree – a gas powered car could see its market share should it be developed
Be interested to know your thoughts regarding EV’s
N.Ginear,
It’s not the smell which makes a certain type of fuel to be more polluting than others.
EV = EM Radiation = Leucemia
Yes, I know, you don’t see the EM radiation as you see the diesel ‘dirty fumes’. But it is there. It’s a silent killer.
Lol. LPG conversion?
It’s fairly simple to convert a petrol car to LPG.
Landigas in Holland did this in 1970,s all taxi’s etc run on gas… lots of cars in Finland and the Continent also run on gas; the choice is there.
When’s the last time you smelled chlorine gas. I’m going to say never because you would be dead since it is a very deadly, toxic gas.
As a matter of fact (and FACT CHEKING), there is a wide concentration range between just perceiving the odor and letal levels.
Chlorine is a heavier-than-air, greenish-yellow gas with a pungent, irritating odor. The odor threshold for chlorine is 0.002 ppm in air, while for humans, a 5-min lethal concentration in 10% of subjects (LC10) of 500 ppm (NTIS 1996) and a possible 30-min lethal exposure of 872 ppm have been reported (Perry et al. 1995). Data from industrial accidents confirms that workers that breathed chlorine from leaks at 30 to 66 ppm survived, althoug with some slight but permanent lung damages (in some patients these effects progressed to bronchopneumonia, epithelial regeneration, and repair by fibrosis by day 25 post-exposure.
Therefore, you CAN smell Chlorine and still live to tell! Amclaussen.
BTW, I’ve smelled the repugnant odor from busses and (frequently from PEUGEOT brand vans), but I find it very different from the Chlorine odor, that you can sometines easily perceive in indoor swiming pools.
LPG & CNG use in ICE has been around for a very long time. True duel fuel engines,(based on C.I. engines), have also been in use for a very long time, oil pipeline pumps are an example.
CNG in particular is very clean burning and any ICE can be converted but C.I. engines are better than S.I.
Just because you cannot smell the pollution from a petrol car does not mean there is none.
It takes only 10 dollar device such as the carbon monoxide dispenser to arrest it.
Have you ever been behind a petrol engine car when the CAT cleans itself, they stink of rotten eggs, apart from better mileage & more power the modern diesels are getting better, I always put an additive in the fuel when I fill up and when it goes for test it sails through the emissions test and I read that Bosh have invented a device that will when fitted to new engines will better the emissions of the best petrol engines, & remember this if everyone changed to electric there wouldn’t be enough power to charge them. Look at who’s report this was and where their interests lie.
Whatever the fuel used, there will be a cost. What we have is a planet with too many people using too many resources. Anyone volunteering to leave? I don’t think so. So we must do better at storing energy that comes directly from the Sun. Once we have acheived this, our lives should improve.
I’m with Adrian here, we have one resource in this planet and only one atmosphere. We could if we had the will have an immediate impact on daily emissions just here in the UK (and anywhere else applicable) by just stopping really uneccessary journeys such as school drops when the journey is 100% within walking distance, cold engines, petrol and diesel started up, run to the school dropping children off (who would benefit from walking anyway) and the reverse at pick up time. Obviously many children do not live near school but thousands do. I live in a small place of just 2300 dwellings, two adjacent schools totaling about 250 children in all and we surveyed all cars coming to the schools over one week. Out of 97 cars at the schools 61 were local (less than 10 minutes walk away), these figures were the average across the week and this happens twice per day x 266 days per annum with run times of average 3 minutes each journey. That is 1655 hours continuous running for one car. How many schools in the UK?
Anyone remember Malthus? How can this kind of Victorian thinking still be with us?
The problem with this article and many others is it still overstates the problems with diesel, especially with new car choice. Do you buy a new petrol car instead and have 100% more CO2 causing global warming or a diesel that produces a tiny bit more NOx? I would choose a diesel car as global warming will be catastrophic for the Earth. With Euro6, the petrol car is the least best option.
Well its just too many people – which is the real and only pollution problem!
This is not just a slight over population but gross over population. Typical about 20 million would be good a sustainable population for the UK. Yet the politicians do nothing to slow the growth rate (and its not just immigration – but that is an issue) and seem to think that an ever increasing GDP is a good thing.
This is not just about global warming, but the quality and safety of life of everyone.
You don’t have to leave planet Earth to reduce greenhouse gases, just use your legs more. I walk everywhere up to 4-5 mile away. My diesel engined car has a tank that gets filled approx every six weeks. I really only use the car to drop my kids anywhere as their legs get tired quickley. We have an obesity problem too. Kill two birds with one stone.
A commendable article. It is essential that the fear campaign is dealt with using true facts. The simple fact is that the UK has an appalling inner-city public transport system everywhere outside of London which makes it hard to ban cars and vans: as is needed for ideal results.
The present demonising of diesels is part of the new “fear campaign”. Cost benefit assessment (as is normal in say NICE assessments of drugs) is what is needed using the old BATNEEC system for continuous improvement rather than a radical unfounded change. Glad that the government have resisted the eco-nuts so far.
True, and it was the irrational behaviour of the ‘eco-nuts’ that promoted the diesel over petrol policy! Just like biofuels that are wrecking the environment as forests etc are cut down, unintended consequences is the bane of the self righteous environmental green lobby.
Engineering and a scientific approach to problems and policies is required, yet hardly an MP has a STEM degree or background – no wonder our governments are such a mess!
Although not convinced that electric vehicles are the best solution without some dramatic breakthoughs in battery techology
I think many people in the vehicle business have known this for a long time, but government is too much influenced by journalists with little knowledge.
Current developments with direct injection will bring petrol engines much closer to diesel levels of fuel consumption and Co2 emissions.
Direct injection petrol engines also produce more particulates and will need a particulate filter in next EU6b legislation
Recent research shows that petrol engines throw out up to 100 times more carbonaceous particulate matter than modern diesel engines, this largely caused by fuel injection which is more polluting than normal aspiration. As usual the govt. and other bodies simply concentrate on one aspect without looking at the full picture. They simply want to faze out diesel because they are losing out because of the previously lower tax.
Why not just ride a bike! cheeper, cleaner, actually benifits health and safer. Build more cycle paths!
Ok that doesn’t work for every one, but if every one who drove less than 10 miles cycled think what a difference that would make!
That’s fine until it rains or there is snow or even a good frost. Try carrying a tool box or even a 25 ltr drum of oil.
Cycling is something that only the greens or other tree huggers look towards. It doesn’t cure the problems of global warming or vehicle diesel particulates. The public transport system in this country is appalling. It may be fine in towns and cities but out in the countryside you realy take pot luck as to the number of services or even if they are going to turn up. Cycle paths, don’t make me laugh. We in the country can’t function without our vehicles, be they petrol or diesel, so don’t start spouting on about cycle paths, just another waste of our hard earned money.
Graham Taylor, what a shame that you are unable to think critically. Are you really an engineer?
By the way, just to debunk the myth, I’ve ridden a bike in the rain and it still worked…
Pity that you are applying a single solution (see the original article about that sort of issue) to only one aspect. Bicycles are great for what bicycles are good at. But they don’t; carry people, shopping, go very far in a practical timescale, can’t transport goods (beyond a few pizzas) and are slow everywhere that isn’t an inner city. Employers, shoppers, et al don’t have all day waiting for a bicycle to get somewhere. Ambulance, paramedic, police, fire bicycles anyone? The difficulties of transport, public or private go way beyond the simplistic approach, and as someone earlier has reminded us, transport uses resources and requires energy. The more people there are doing so the worse the problem is, and when successive governments also promote distribution of energy demanding technology across the world in pursuit of economic growth the inevitable happens! Yes we need better systems, but they have to fit in with all other systems, so it would be nice if there was some constructive comment with rational solutions to make. Though I am sure that Halfords would love to sell bikes to everyone, how many could we get by swapping them for a car I wonder!
Sorry, but I’m with Graham Taylor comment on 7th November 2017 at 2:12 pm on the true “convenience” of bikes in large cities. Here in Mexico City the “Eco-Cycle Paths” are almost empty, and not just during rainy season, because bikes are impractical. There is a very adverse effect of just planting Cycle paths along previously speedy and free flowing streets: It is called the “LAW OF UNINTENDED CONSEQUENCES”, because those seldom used Cycle Paths provoque serious car and bus traffic jams by reducing the available car lanes. Here you can testify how stupid is to get long lines of ICE vehicle congestion, along the almost empty Cycle and Public Bus exclusive lanes. And those brave (and stubborn) ones that insist on furiously pedaling, are the ones most damaged, because they are directly breathing (at highly increased metabolism rate) the concentrated exhaust emissions of the stopped but engine running vehicles! What happens is that ignorant politicians quickly join the Eco-Phanatic rows because it is “the nice and proper thing, and earns more votes”. Last city majors are sold on the large “Eco-Buses”, that paradoxically, are Diesel fueled. Lack of extensive maintenance of those (mainly Mercedes and Volvo Euro-V powered buses) are visibly polluting not only with their smell, but emissions and noise. The heavy weight of those buses caused the early failure of the street pavements, and required an expensive reinforced concrete re-pavement. Another UNINTENDED CONSEQUENCE of the “Exclusive Bus lanes” is that those impede the free flowing left turns (we drive on the right side of the road, no pun intended), and that Left-Turn prohibition causes increased pollution from the newly created need to make 3 more turns to the right and increased driving distances. And those large, too-wide Bus-Only lanes are really non-sense, because anyone armed with a simple hand stopwatch and two working neurons can attest that even at rush hour, the quantity of passengers carried on those buses is actually SMALLER, when measured as passengers per metre of road width per hour compared to the too vilified private cars(!).
Riding along on your bike, alongside or behind all those polluting vehicles, sucking all that air pollution into your lungs day after day on your way to/from work! Sorry but it seems like a recipe for lung disease to me. I agree that pushbike riding is generally a healthy pursuit – but not on busy town/city roads.
This country is in the main cold wet & windy. Riding a bike is not pleasant & requires dressing up in appropriate clothing & safety gear plus arriving hot & sweaty at your destination. Warmer, more clement, climates favour bike riding (& mopeds & motor bikes) Far better to be cocooned in a protected warmer car
The problem with all these so called facts, is that they are biased, depending on who produces them.
Take the catalytic convertor (please do), used on petrol engine cars. The data used was from a California site, with ambient temperatures in the high 20’s, where exhaust temperatures reach optimum temperature with 30 minutes. Fine if you live in the states and drive long distances to work, then on balance a petrol engine car will emit less CO2. Transpose that to a climate where the ambient temperature is lower for 3/4 of the year, so the exhaust takes longer to heat up and driving distances for many are much shorter. The catalytic convertor is as much use a a toilet wipe over the exhaust.
So please, if you want to quote facts, then take everything into account, not just facts to prove a point.
And make sure your facts are right too – catalytic converters have no impact on CO2 emissions, they reduce NOx emissions.
Generally diesels emit less CO2 than petrols: their thermodynamic cycle is more efficient, but they do emit more NOx and particulates. So, if you’re most worried about global warming, get a diesel engine; if you’re most worried about your health, get a petrol engine.
This is why anyone who actually thinks about a statement made by people pushing an adgenda can always find the holes in the argument. I agree 100% with your view, well said.
Typical time to “light-off” of modern Cat converters is in the vicinity of 5 minutes or less. Ambient temperature has a distant relation to inside temperatures of catalytic converters. while the coolant temperature you look at your instrument panel is slowly rising in cold climates, the insides of the catalytic converter are in theirown environment, where the heat from the combustion chamber and the fuel-air mixture are governing the light-off. Source: “Light-Off Behavior of Catalytic Converters” C. P. Please, P. S. Hagan and D. W. Schwendeman SIAM Journal on Applied Mathematics.
Vol. 54, No. 1 (Feb., 1994), pp. 72-92
Nobody is giving me a sense of proportion on this, as pollution from heavy goods is not mentioned. Overall what percentage of NOx and PM is from cars, compared to amount from heavy goods. If its only a few percent, as I suspect, we are wasting time and effort looking at the wrong thing.
A 2016 report from ICCT estimated that light diesel vehicles contribute 6 times more waste than heavy diesel vehicles, when emissions are measured during real driving. These figures relate to mainland EU countries where real driving emission tests are mandatory for HGVs and public transport vehicles.
In 1898 in New York there was a symposium aimed at finding a solution to the pressing urban problem of how to deal with horse emissions (notably manure and urine). No solution was found until the 1920s, when Henry Ford came up with an alternative for urban transport. Plus ca change….
EXACTLY !!!
My thoughts exactly. For example look at buses currently running in Southampton. These older ones tend to emit lot of visible smoke. If you compare a emissions of a bus which make regular start/stop running for a whole day compared to a car/suv which would most likely travel in to the city in the morning and go out in the evening there must be a huge difference. So it might be beneficial to allocate resources to improve these kind of emissions rather than banning cars
Original data to make MPs decide to adopt catalytic convertors was presented by an industry that would make money out of it, and in point of fact an efficient lean burn engine was far better for the environment, ignored by Conservative politicians, who were probably making money out of the car industry adoption.
Also did not mean to say emit less CO2, as it will always emit the same, just that emissions will be greater in a country with a lower ambient for 3/4 of the year.
this diesel vs petrol banter is a side-show
for ultra people dense urban city areas we need to remove combustion transportation, personal & public, thats where it matters and thats exactly where the politicians are ‘not-really-addressing’ the problem, queue usual side-step, blindspot, but the pressure is now on
Interestingly, the article only looks at engine emmisions. Fine particulates are also introduced into the environment from tyre wear and brake linings (significant quantities) and from biomass combustion. Coarser particulates predominatly come from soil/land ersoison and mining. Also if the idea is that electric cars are somehow a panacea , if we were all to convert to them, we would have to bring on stream an awful lot more power generation to cope – I think the EU recently estimated that at 80% adoption, this would account for 15% of all electricity produced in the UK. That implies a large increase in CO2 to go with it – or maybe the good people of Westminster would like a couple of Hinckley Points in their borough? If mass transportion of goods and people is still going to be inevitable there WILL be a downside.
On the other hand, after BREXIT, I suppose EU sourced data will no longer be relevant so we can do the patriotic thing and pretend there is no problem or would that be considered to be wrong and unstable?
Hi John,
I am just starting out on a little project looking into the diesel, petrol issue. You mention some very interesting things in your post. Do you know much about the subject? I am a car dealer in Norfolk and get asked the question “what’s the diesel car ban about” A LOT. Thought I would do a bit of my own in debth research
We will still have to abide by EU regulations after BREXIT if we are to maintain any kind of car industry in the UK, which is probably the biggest in Europe (for now). There is an awful lot that the BREXITERES never realised. Nevertheless, I am still in two minds because I am considering a new Range Rover where I have 4.4 Diesel and am thinking about a 5.0 Petrol. Range Rover have a video that states that the balance between both their engines efficiencies balance the omissions. Maybe they are right or maybe they just needs to shift a load of Deisel cars that they made some time ago.
Yes, and to replace fossil fuels we will need a minimum of an extra 500TWh (at 2016 rates of consumption) of energy from some other source assuming similar efficiencies to fossils, ie approx 60GW of generating capacity assuming electric. And massive infrastructure upgrades or revert to Victorian long distance journey and goods delivery times.
In UK it’s easy to tell whether you ride behind a diesel – thick black smoke. Usually buses, lorries, trains, ships.
And when you tell a bus company, all they reply is – we are aiming for the highest standards, bla bla bla.
The idling engines in Birmingham New Street stations made me switch to the bus. And the 900 bus always late made me (wish to) switch to a car, to get one hour per day for exercise instead of waiting around.
Luckily I lost my job and the need to commute.
Ban **all** modes of transport using ICE and replace with electric-powered and bicycles. But, there remains the problem of PM and tyre-abrasion: minor issues for the occasional vehicle, but also a danger-to-health nuisance where dense traffic is concerned.
The only credible way of removing the polluting effects, but hardly practical! Not possible to carry much shopping on a bicycle and long distance travel will in effect cease!
Why do politicians and usually academic articles always concentrate on cars? When will we get a factual article which shows the percentages of pollution contribution from cars, buses, trains, heavy goods vehicles, light goods vehicles and industrial machinery (diggers etc.). Perhaps when this is received we will be able to assess the impact on our lives of living without diesel. Has anyone seriously looked at ways of removing more NOx and particles from these engines before taking knee jerk reactions.
Finally, what contribution to NOx do gas turbines make? Industrial ones tend to run on diesel or gas. I believe that aircraft gas turbines also produce NOx, will the next move be to stop air travel?
Lets get all of the facts before making changes.
On Gas Turbines, many years ago (probably in the 80’s) the design of the combustion chamber in gas turbines was modified in order to reduce the (previous) need to inject water to lessen NOx emissions. The “Dry SoLoNOx design reduced peak temperatures and reduced NOx emissions considerably. More recent designs produce even lower specific concentrations of NOx. Amclaussen.
While acknowledging that the article above relates to internal combustion powered vehicles and the related air pollution from them – I think it’s worth pointing out that I have not seen equivalent figures for the amount of CO2 and other pollutants produced in the manufacture of an electric vehicle, and in particular its battery. Talking to a respected industry insider recently I understand that the CO2 emissions from the production of a leading electric-only car battery could be equivalent to those created by 60K miles of emissions from a conventional ICE vehicle. Can anyone confirm if this an accurate estimate? Also, is any organisation producing unbiased figures that allow us to compare both the tail pipe emissions as well as the manufacturing emissions from different classes of vehicles?
But where is that pollution emitted? It’s preferable to emit pollutants on an industiral site where they can be dealt with than in a town centre where people will breathe them in.
Assuming the battery manufacturer is paying their electricity/power bills, then the cost to manufacture the battery in terms of CO2 is reflected in the price of the final product. To drive 60000 miles at a cost of say£0.15/mile would cost £9000. Does the car battery cost £9000? If the battery manufacturer is totally solar/hydro/nuclear powered, then there is no CO2 produced during the manufacturing process.
We should try our best to reduce CO2 in case so-called climate change is real. But we should not lose sight of the fact that CO2 is just plant food and will ultimately end up as plant material, whereas NOx and PM are slow killers with effects similar to smoking. Unfortunately the EU is predominantly focused on CO2.
Yes, everyone knows that electric cars produce less CO2 for their life cycle analysis compared to ICE. And none of the studies included the 7KWh of electricity needed to refine a gallon of fuel, so that solves the electricity requirements for charging. At the end of the day electric cars are 90% efficient vs a 25% ICE
https://www.theguardian.com/environment/2017/oct/25/electric-cars-emit-50-less-greenhouse-gas-than-diesel-study-finds
It is always nice to see someone applying a bit of common sense and suggesting a look at the whole picture before going off down the route indicated by the journalists that are driven by ideology rather than the real scientific picture. If you want a realistic view of the climate change world look up the article that covers the out of control emissions of a deadly ozone killing VOC by dozens if not hundreds of foam insulation producing manufacturers in China. The world must really laugh at the sacrifices politicians like Khan are willing to impose on people in such a small country as the UK. They give in to the lobby that think that if it rains every Tuesday for 6 weeks the next time it rains it must be Tuesday. Dyson could not interest the politicians in a solution that may well have solved the problem.
Everyone forgets about aircraft emissions. Kerosene particles rain down on most cities from the local airports. They cover huge areas & for most of the day, every day. They don’t have any kind of filter system at all. Next is all of the houses that have gas central heating; this also has no clean air system to filter or clean the output exhaust. Every one is brainwashed into thinking they have to have gas central heating when there are alternative ways of much cleaner systems. Get rid of aircraft over cities & gas central heating & that would make most areas a lot cleaner!
I thought that bunker oil is the most polluting fuel used in transportation. That does not mean that jet fuel is much better, we should abandon all fossil fuels.
Yes, don’t forget the shipping industry and the heavy fuels they use (in tonnes). The emissions from which rain down on our oceans and into the aquatic food chain. (Fish for dinner, anyone?)
Perhaps we could stop ships from dumping their refuse into the seas too!
Apparently Sylvia, you don’t have the slightest clue about how clean are modern aircraft engines (Aka turbines). When measured on a per kilometre-Passenger or even kilogram-per kilometre for cargo basis, those engines and aerial vehicles are among the least polluting ones. You need to establish some measurable criteria before qualifying jet fuel pollution.
Gas Central Heating releases zero particulate emissions. Thus results in clean air in residential streets.
A log burner however (endorsed by various green incentives) releases vast quantities of lung harming soot, creosote, PM10 and PM2.5 emissions, not to mention the foul odour that permeates throughout residential areas. Pellet burners are no cleaner.
Agreed. It’s time that Govts globally got to grips with taxing aircraft fuel. We have got into a habit of expecting to be able to fly abroad twice a year and damn the consequences. Still, kicking the can down the road won’t make the problem go away, particularly when the world expects to be flying more and planning yet more runways.
Lets have more facts.
•carbon monoxide (CO), petrol down 63%; diesel down 82% since 1993
•hydrocarbons (HC), petrol down 50% since 2001
•oxides of nitrogen (NOx) down 84% since 2001
•particulate matter (PM), diesel down 96% since 1993
see https://www.smmt.co.uk/industry-topics/emissions/
In fact Diesels have been a victim of their own success.
To answer your question, by concentration, CO is the biggest pollutant and petrol engines emit the most making petrol the worst. Shock, horror! The good news for Petrol-heads is CO levels are well within EU limits.
Its no good going on about where we are -we have made the engines and now the poor people will drive them until a prion becomes second hand – In the meantime there is a solution -instead of scrapping the car convert it to LPG. as this will give better results than any combustion engine currently available – But there is a problem -Car companies will not benefit. EU limits means less deaths not a clean environment . Having an answer that is already there and can instantly make a difference but ignored by the government shows the power that the status quo hold.-No advertising No pumps No policy.The rest of Europe who are well ahead of us in this type of fuel.
It wasn’t that long ago when Ford and Vauxhall used to offer factory dual-fuel petrol/LPG options for their popular models. There was a grant for conversion and LPG had a more favourable duty rate. Now, the price differential between LPG and petrol has narrowed making it not economical unless you drive 25,000 miles a year. LPG is definitely better for NOX and much better than diesel for PM10, so ideal for an urban environment.
I can tell you that not all is ‘fine and good’ with LPG fueled vehicles. Even the better gasoline (“petrol”) to LPG-Conversions still have measurable “Fugitive” emissions of hydrocarbons. I work for the Mexican Petroleum Institute, and we happen to have some of the best emissions laboratories in entire america, capable of measuring and detecting practically ALL emissions from a vehicle (even including some rare especies coming from rubber tyres when the vehicle was driven “hard” a few minutes before). When the Mexico City Major several years ago became too-enthusiastic and “sold on” LPG conversions, we demonstrated that the fugitive emissions (in practical real-life operation (including LPG refilling stations), did produce objetionable contributions to the most urgent MExico City problem: ground-level ozone levels, as hydrocarbons are the worst precurssors of ozone in Mexico City. When evaluated in a through manner, including EVERY pollutant from EVERY souce in the LPG vehicle, and correcting for the lower mileage of the LPG against petrol, the supossed advantages of the LPG largely diminished its apparent attractiveness. As with electrical vehicles, it is extremelly important to take into account the WHOLE picture. Our own evaluation of a 100% electric against an Hybrid, revealed that the Hybrid has actually slightly LOWER life-cycle emissions than the pure-electric vehicle. Amclaussen.
I am interested in this issue, and questioned the authorities many years ago on why I could see black clouds coming from modern turbo diesels that have passed emissions tests. Perhaps due to “chipping”. I feel I am missing something when a 5 litre V8 turbo diesel can pass the same emissions test as a modern small car. The elephant in the room is engine sized.
They will also have the same emissions problems. To achieve similar levels of fuel consumption they will have to be lean burn so the three way catalyst will no longer function (this actually works best with a slightly rich mixture). They will also have to have higher maximum cylinder temperatures and pressures than current petrol engines (basic Carnot cycle limitations) which increases the production of nitrogen oxides. A similar thermal efficiency will have a similar emissions profile.
Best regards
Roger
It all depends on what/how you measure. If you measure % or ppm in the exhaust stream the size of the engine or vehicle doesn’t matter. If you measure grammes per person kilometer or payload tonne kilometer you will get a different answer regarding engine and vehicle size. Current measurement regimes are a mix of both.
What is also usually missed from these measurements is a real use profile. The three way catalyst used on petrol engines has to heat up before it is effective. A lot of short, cold engine, journeys will create significantly greater emissions than the equivalent person/tonne kilometers made with an engine at normal working temperature. In this area petrol engines are generally worse than diesels.
Best regards
Roger
I too have written to a number of people such as the CEO of the SMMT and the mayor of London asking why visible soot from almost all diesels was being ignored. This problem has been obvious for decades. The car companies have been sitting on technology so as to increase returns to shareholders.
In short: one is bad, the other is worse. Not only by relative measures (per person, per km, per etc.), but by absolute ones that are much more consequential and enduring: impact on the planetary cycles that support life, human and all other species health, etc. Fossil fuels must remain in the ground, now. They are all bad by different degrees.
https://www.theguardian.com/environment/series/keep-it-in-the-ground
We do have good substitutes for all of them, we need the will to change. Do we have it? I don’t know.
Many posts have missed the key points: we can’t say that equivalent sized petrols or diesels are “better” than each other until we look at real world emissions. It’s clear that the EU test cycle was lobbied by the manufacturers and that they’ve been hiding behind if for 2 decades regarding diesel emissions. I have never bought a diesel in 30 years because it was “obvious” to me that someone wasn’t telling the truth. Don’t tell me that “Gordon Brown encouraged me to buy diesel”. Everyone has eyes and a nose and even the newest diesels produce visible soot under acceleration. The solution? Charge all diesels depending on their PM and NOx and plough the money into EV and H2 infrastructure. That way, you link the cause of pollution to its clean up and the polluters pay.
Parden me sir, but my engine is a 6.6L V8 diesel, and you will NOT find any soot coming from it at all. Even revving hard it is lower than any small 1200cc car, Petrol or Diesel.
Rape oil is the fuel of SENSIBLE PEOPLE, it performs as diesel, YOU CAN DRINK IT, and no pollutants. All this subject is a Scam from Government
Strange about the Anti-Diesel propaganda given an independant Science based article cites that modern direct injection petrol engines create more particulates than a pre-DPF diesel.
https://www.sciencedaily.com/releases/2017/05/170523144338.htm
Funny how this debate raised its head when the price of oil plummeted, so burning 30 percent more fossil fuel seems to be the best answer all round !
A recent article about Swiss research, found that petrol engines created more emitted pollutants than diesels in some areas. But this has not had much publicity, that I have seen and hasn’t come up in any public discussions on the matter, that I have heard:
Looks as though the link was moderated out of my previous submission, so here it is again:
http://lenews.ch/2017/05/18/petrol-vehicles-more-polluting-than-diesel-ones-according-to-swiss-research/
The EV argument falls down when the energy density equivalent of filling a vehicule with fuel is considerd. The generally recognised energy transfer out of a fuel pump is 6Mw per minute. It takes about 6 hours to fully charge many of the tesler cars to give a range of 250 to 300 miles. Towing say a trailer or caravan will reduce the range by 30%. To achieve the charge rate requires a 43.5 A charger circuit. The distribution supply network in the UK would not cope at a local level with everyone in the street charging their cars at night. The diversity factors used by engineers to size cables would result in local overloading. In one of our local streets it has ben calculated that more than 6 high performance cars charging at the same time would trip out the local supply.
One area of fuel mix not considered at all is gas assisted diesel. There are a number of companies advertising the improvements this approach is claimed to give. One is a significant performance improvement, particularly increased low end torque. The other is a 90% reduction in particulates, and an improvement of 4% in fuel consumption.
The engine has to be re chipped to cater for reduced diesel consumption and the injection of gas, which burns clean at low temperatures. This technology is has never been properly analysed by any “independent authority” Why not ?
So then, it is back to horse carts and carriages, is it?
Then the only diesel engine in town will be the Caterpilar front end loader picking up horse manure.
BTW, has no one researched making an Allam cycle vehicle? I expect the weight penalties for the air separator to be severe, unless the oxygen is used only as made. The thing would be efficient, regardless of fuel, and the by-product could be a full tank of pure water, and a full tank of food grade liquid carbon dioxide. How interesting would that be? Zero tail pipe emission because there would be no tail pipe.
At present the road tax is based only one the rate of unit CO2/km. And not the actual emissions. If the tax based on {rate}x{mileage}, you would have the answer directly. At present the driver doing 4,000 km per year at 100 units of CO2/km (400e3 units of CO2 per year) is paying more than the one driving 30,000 km per year at 70 units of CO2/km (2,100e3 untis of CO2 per year). So 400e3 emission units is paying more tax than 2,100e3 emission units (5.25 times more). The system does not discourage to emit less. This current road taxation on rate not on usage is incorrect and much more polluting and relevant than the difference diesel/petrol
The problem of diesel air pollution and nitrous oxide (N20) being a greenhouse gas dangerous to the Ozone layer has been around for years. Back in the late 1960’s the governments wanted to ban diesel engines because of their pollution, but then the oil crisis in 1973 and 1979 happened, with the result that fuel efficiency became a more important issue, and nothing was done, in fact the government promoted the diesel engines. Even today they are only just starting to talk about the problem and its devastating consequences, including the particle pollution of Diesel exhaust.
The answer is to go electric motors and Frictionless Electric Brakes, check out: https://contest.techbriefs.com/2017/entries/sustainable-technologies/7459-0325-0820027-frictionlesselectricbrake
I have always had diesel vans all 2.4L and since the early 80s my vans have progressively given greater mileage, they went from just over 280 miles from 75 litres to 500 miles in my newest van for the same 75 litres so the efficiency has almost doubled & I have always had automatic boxes, the latest one being duroshift (electronic) so has anyone taken into account the difference in mileage between petrol and diesel?
Bazzer.
I can assure you that if you drove behind my diesel you would be hard pressed to tell that it is a diesel. It is a Euro 6 citroen 1.6 ehdi and returns an average of around 55 mpg mixed driving. The inside of the tailpipe can still be seen as metal it is not covered by sooty deposits. I am sure it’s No2 production is higher than a petrol car but not much . The main issue in our towns and cities is the massive traffic peak caused by the school runs and the stop start flow of traffic due to too many vehicles and people in a small area. The uk has only 1% of land built on. We need to spread out.
Remember all clever folks, that diesel oil will be burned anyway somewhere even you remove all diesel cars from the roads !
Why, because amount of aircraft kerosine dictates how much oil is refined to kerosine, gasoline, diesel, heavy oil, etc. Refineries are going to make that diesel oil anyway and someone somewhere is burning it for some purpose.
Innovation is the key to progress. Better than hand wringing. Fully variable valve timing has great potential to reduce emmissions. It allows reduced engine size, controlled compression rato, re-breathing of quench gasses, higher efficiency at a wide range of speeds and loads, engine braking, catalyst heating, turbo boost, etc. It is easily possible to implement . Most current systems only scratch the surface of what is possible by being only phase change systems, or having very limited and fixed timing changes. About £200K would build the first system. Full development and testing would of course take a little longer. Adding the cost of another engine control system seems to be strongly resisted by the big manufacturers, but if soembody raised the bar, they would all have to follow.
Oh well bring on HYDROGEN evs, no pollution at all, convert all evs to Hydrogen, no long recharging times, HYDROGEN is easily produced by splitting water, you could have HYDROGEN producing Electric charge, using the only discharge WATER back into HYDROGEN could give 75% EFFICIENCY potentially. Beat that, a
load of rubbish is talked by flat earth petrol heads, by the way I had a discovery 200 tdi for 13 years I loved it .
Nick: Unless you sit down and pick your old scientific calculator to do some serous numbers, you cannot simply assume that Hydrogen is the cure-it-all solution. Hydrogen has undoubtedly the tremendous advantage of producing PURE water vapor as exhaust… 100% non polluting! BUT, storing, compressing and producing the large volumes of hydrogen needed to fuel all cars and trucks, requires ENORMOUS quantities of energy, costly vessels and the needed infrastrucuture is not cheap. Your phrase: “HYDROGEN is easily produced by splitting water” is completely misleading: water molecule splitting by electrolysis demands A LOT of electricity! There is no free lunch. I respectfully invite you to perform some calculations (after all, we are all engineers, don’t we?) so lets start to back up our claims based on actual numbers.
Some knowledgeable people had already done those numbers, one of them is: Why a hydrogen economy doesn’t make sense
December 11, 2006, Phys.org
(Read more at: https://phys.org/news/2006-12-hydrogen-economy-doesnt.html#jCp )
“In a recent study, fuel cell expert Ulf Bossel explains that a hydrogen economy is a wasteful economy. The large amount of energy required to isolate hydrogen from natural compounds (water, natural gas, biomass), package the light gas by compression or liquefaction, transfer the energy carrier to the user, plus the energy lost when it is converted to useful electricity with fuel cells, leaves around 25% for practical use — an unacceptable value to run an economy in a sustainable future. Only niche applications like submarines and spacecraft might use hydrogen.
“More energy is needed to isolate hydrogen from natural compounds than can ever be recovered from its use,” Bossel explains to PhysOrg.com. “Therefore, making the new chemical energy carrier form natural gas would not make sense, as it would increase the gas consumption and the emission of CO2. Instead, the dwindling fossil fuel reserves must be replaced by energy from renewable sources.”
While scientists from around the world have been piecing together the technology, Bossel has taken a broader look at how realistic the use of hydrogen for carrying energy would be. His overall energy analysis of a hydrogen economy demonstrates that high energy losses inevitably resulting from the laws of physics mean that a hydrogen economy will never make sense.
“The advantages of hydrogen praised by journalists (non-toxic, burns to water, abundance of hydrogen in the Universe, etc.) are misleading, because the production of hydrogen depends on the availability of energy and water, both of which are increasingly rare and may become political issues, as much as oil and natural gas are today,”
Read more at: https://phys.org/news/2006-12-hydrogen-economy-doesnt.html#jCp
An interesting report on real world testing of petrol engine emissions:
https://eandt.theiet.org/content/articles/2018/03/most-popular-cars-need-substantial-improvements-to-nox-emissions/
This suggests that however you approach the conditions for a high thermal efficiency (reduced fuel consumption and CO2) of high pressures and temperatures and excess oxygen you will get higher levels of NOX.
Best regards
Roger
“most popular cars need subtantial improvements to NOx emissions…”
Yes Roger B, we find that the most popular cars here in Mexico City are the smaller sedans like the VW-Jetta, VW Golf, the GM Cruze and Aveo, The Ford Figo and others very similar to them, are indeed the higher producing NOx offenders. It is related to the quality and cost of the Catalytic converter (impregnation level), and the calibration and design of the entire fuel injection system, that produces higher NOx levels than larger, costlier sedans of the very same manufacturers. But NOx is much more related to combustion chamber temperature, first, then combustion chamber design, and then to smaller engines working harder than larger ones.
We have reduced (halved actually) the NOx levels by simply upgrading the cooling system (larger, better coolant radiator, coolant pump, larger radiator fans and higher flow thermostat, better spark advance calibration ). Our conclusion is that car manufacturers skimp on component size and efficiency, and that the same engine can produce LOWER NOx emissions if carefully adjusted and provided with better cooling! Price increase was not huge, but for car makers it seems that some extra dollars spent in their products would mean their instant economic demise (rampant capitalism at work).
I have read the scientific paper generated by the link “also causes cancer” in the above article.
I have to say, that the authors of this paper state that there is NO EVIDENCE that particulates cause cancer! They do state that it may cause respiratory problems, and heart attack, especially for those already at risk, or suffering from asthma. The study shows that risk increases with peak level emissions. It seems clear to me that the solution is to ban diesels from city centres and high density populated zones. However, I’m sure that’s not what the treasury wants to hear, especially when modern mid engine diesels are doing 55 – 70 mpg, which means less tax dollars at the pumps, as we don’t need to fill up as often.
It was not long after the article was posted that the government announced the end of I/c engines by 2040. This madness has caused the UK car industry to lose direction and blame the foolishness on Brexit so as not to upset the government advisors.
The electrification without reliable power could mean the UK stopping for a few weeks over winter and of course, electricity prices are still rising in real terms because of the over-subsidised white elephants that give us power when nature allows rather than man needs it.
Sadly, for the UK anyway, the rest of the world is taking no notice of our energy-madness.
Fact update.
https://uk-air.defra.gov.uk/assets/documents/reports/cat11/1212141150_AQEG_Fine_Particulate_Matter_in_the_UK.pdf
Have a look at chapter 4.2 pages 79-85.
UK PM2.5 emissions – road transport (exhaust) 2015 5.7 ktonnes (10%), 2020 2.0 ktonnes (4%)
road transport (non-exhaust) 2015 8.2 ktonnes (14%), 2020 8.8 ktonnes (17%)
The projected figures for 2020 show that the Euro emissions standards are working. Non-exhaust emissions is a more significant problem, resulting from road abrasion, brake wear and tyre wear.
Targeting the diesel based on the real facts is therefore totally unjustifiable.
Politicians (ignorants) and Eco-Phanatics (obsessed) need a ‘villain’, and that villain is CO2… While there are other gasses with many times the “greenhouse” effect of CO2, like Methane. Those dumb politicians and strong phanatics of the climate change have even weighted their measures towards a “CO2 is the baddest enemy” attitude.
Methane warms the planet by 86 times as much as CO2, according to the Intergovernmental Panel on Climate Change.
But policymakers typically ignore methane’s warming potential over 20 years (GWP20) when assembling a nation’s emissions inventory. Instead, they stretch out methane’s warming impacts over a century, which makes the gas appear more benign than it is, experts said. The 100-year warming potential (GWP100) of methane is 34, according to the IPCC.
The natural gas promoters also want Methane to be largely ignored. And there is the question: How much methane is released from ALL sources, like cattle and earth sources like Hydrates decomposing?
A very interesting series of posts and quite emotive. I agree with the previous respondent that, when safe storage is sorted, hydrogen fuel cells are the way forward. Fuel is generated via you solar panels (this summer would have been ideal) A super capacitor (or ZapGo) to get you moving, recharged via regenerative braking will reduce the particulates produced on EVs from the high wear on brake pads. Sorted!
Perhaps if we spent a bit more money on public transport in urban areas especially trams on high demand routes we would have less pollution and less congestion from diesel or petrol cars. And a bit more joined up land use transport planning, that for the last 30 years built an autocentric environment with out of town shopping centres, et al.
eg the traditional flat European city
I agree with John Daglish that public transport in the UK has been largely ignored for generations, and the chickens are now coming home to roost.
Regarding Hydrogen, this will be very expensive to produce from methane and as yet there is no other economic means of generating this. But, an additional, and conveniently forgotten issue, is that burning hydrogen produces nitric oxides as well as pollution at source of production.
The negative effects of diesel depend on the driving cycle. Diesels are very polluting on an urban start stop cycle that has not been compromised. At steady revs cruising down a motorway fuel economy is at a high and particulate emission at a low. At this end it is clean. Tax conventional diesels entering urban areas.
This leaves us with hybrid diesel. Given the cost efficiency of diesel, I am intrigued to know why there are no hybrid diesels on the roads. There are many, of a sort, on the rails. A diesel engine running at constant optimum speed to charge modern batteries would be an extremely cost effective mode of transport.
Quote,
Well maintained diesel vehicles have quite similar levels of particulate emissions to petrol cars,
Unquote.
Thats important, once vehicles are out of guarantee the majority are not maintained to manufacturers requirements, does not matter much for petrol but it certainly does for diesel, so no, over the life of the engines diesel does not have similar levels of particulate emissions to petrol cars, as diesel engines last far longer than petrol engines the particulate emissions problem can only get worse, hence the black smoke from older diesels which did not do this when new and well maintained.