Decades of diesel use in Europe have created a public health crisis

To play a devil advocate, there could be a lot of non-human allergens, with a most common culprit being pollen.

It’s worth saying the average pollution levels are not capturing the full health impacts. You could easily have a spike along roads due to diesel but at the same time a reduction in the average, because roads are only one of the emission sources. But they are where people spend a lot of their time, in cars and buses in traffic, walking, cycling; and nearby many people are living, and going to shops and cafes. A lot of the effects of pollution are hyper local.

London is the only city in world that turns everyone's snot black, not even Delhi or Beijing does that.

> As an aside, I moved from London to the Bay Area for a number of years. Many of the Londoners I knew who moved there developed terrible allergies after a few years.

This is common among people that move from one region to any other region.

Do you know any specifics of why the Bay area is worse than London? Or what causes it?

>>it's clear that London's air quality has steadily improved over time:

That's not what the data you linked show, though. You charted Sulphur Dioxide only, but when you look at say PM2.5, there's not even data for the whole period (09/1993-09/2019):

>>Warning: Valid PM2.5 Particulate measurements are available for only 37% of the requested period.

This means they've got data on <10 years, out of the 26 years in the period.

At least for some pollutants that are widely studied and linked to mortality and negative health outcomes - such as PM2.5, PM10, NO2, there does not seem to be an "improvement", based on these data:

https://www.londonair.org.uk/london/asp/advgraphssiteplot.as...

"Dieselisation" of cars in Europe: https://www.eea.europa.eu/data-and-maps/daviz/dieselisation-...

Health effects of diesel Particulate Matter: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1440-1843...

As mentioned in the article car tires also pollute the air so replacing diesel with electric may not be sufficient though a very good step.

We hit >50% electrics for new car sales here in Norway earlier this year. It's exploded over the last couple of years, only 5 years ago only a few % were electrics..

And, coincidentally, the other day someone remarked that (in the Netherlands) the price difference between diesel and benzine has never been smaller, causing an ever decreasing cost benefit to fueling a car with diesel

It is mentioned though:

https://www.bbc.com/news/world-asia-india-49729291

https://www.reuters.com/article/us-china-pollution-beijing/c....

People do give a damn. Unfortunately governments around the world aren't often leaping to take effective action. It's the same with environmental issues in general.

You're right that the average air above London is often (not always) pretty clean compared to the world's most polluted cities. Right now I can look out my window and clearly see buildings that are several km away. Today, at least, there is very little visible haze.

But the real problem is London's narrow, busy streets with heavy motor vehicle traffic in very close proximity to where Londoners live, work, walk, go to school, etc. Anyone who spends much time in Central London is spending a significant portion of their lives in close proximity to the exhaust fumes from thousands of vehicles daily, so exposure to toxic pollutants in London is much worse than many measures of average air quality suggest!

On the bright side, there has been a noticeable improvement recently thanks to initiatives like the Central London ultra-low emission (ULEZ) zone, and the increasing numbers of electric taxis replacing the old diesel ones. One major area that still needs improvement is the buses - there are now some electric buses, but still far too many old, polluting diesel ones.

> Some parts of the world are still living in conditions resembling the Great Smog of London

Those parts are usually in the same economic stage that London was when it had a similar air quality.

When a society crawls its way out of crushing poverty, there are more important things to use the new resources for than air quality. Once those are taken care of, all known societies have fixed the air situation.

The other big cities outside London are definitely worse, Paris or Berlin are much more affected by the use of diesel because both France and Germany have a higher proportion of diesel cars compared to the UK

People tend to aggregate in and around the major cities, which makes the health crisis bigger than a land-area quotient.

Yeah you can sometimes see it in the tunnels. One really should be able to see pollution in like 20 meters of air...

They do this because statistics don't sell news, emotions do.

Would be interesting to see if you can measure any quantifiable effect from wearing the mask.

Yes, gasoline engines emit less NO than (old, pre-Euro6) diesel engines. Their particulates emissions may be higher though. You can see the exact values allowed here: https://en.wikipedia.org/wiki/European_emission_standards

It's a trade off.

Diesel engines are more efficient at using the energy in the fuel and as a result produce less CO2.

However, diesel engines generally produce more NO2 and particulate emissions which causes local pollution. There are technologies which mitigate these pollutants for diesel engines (such as urea injection and exhaust gas recirculation) which are required in the US, but I believe there is less stringent requirements for them in Europe.

I feel like it does explain this, although it's not a Wikipedia article so it doesn't break them down into a nice table for you.

NO2 output is higher for a modern diesel engine, and NO2 is poisonous. Not like "Oh my god I think I breathed some NO2 now I need to go to hospital" poisonous, but it's bad for you and wasn't there anyway. If Europe had decided it hated diesel and petrol remained more popular (as in the US) there'd be lower NO2 emissions in London.

PM2.5 (tiny particles) is higher for diesel. Again, breathing in a tiny particle that will then permanently get stuck in your lungs, damaging them in a minute but essentially irreversible way, is not going to send you to ER immediately, but it keeps happening and cumulatively, especially over a population, that means deaths.

As the article also points out PM2.5 doesn't even go away if you got rid of internal combustion engines. Just rolling at speed causes tiny pieces of the surfaces that come into contact to break off, probably a racist cyclist even emits PM2.5 though nothing like a diesel truck. So this isn't a problem we can entirely solve, but things like ULEZ aim to make it better, the argument is largely that they aren't enough (and apparently for this journalist, won't ever be enough).

Here is a paper using diesel cheating to estimate health effects of diesel cars: http://ftp.iza.org/dp12427.pdf

One cheating diesel car in 1000 cars increases ozone, PM2.5 pollution by 1.33%, 1.99% respectively.

Each additional cheating diesel car in 1000 decreases child birth weight by 0.19%, causes low child birth weight 1.9% more often and causes 8% more visits per quarter per 1,000 children of age 0 to 4 to doctors because of asthma.

So yes, comparable American cities would be healthier. Having less taxes on diesel was a huge mistake in Europe. My guess is it was an attempt to burden transportation industry less with taxes. Plus lorries can do tax arbitration by filling up outside of countries with high diesel tax (so you wouldn't want too high of a diesel tax because of the "laffer curve"). This caused this whole innovation of having consumer diesel cars, even though they are more expensive, complicated and heavy. If you take into account weight and production cost it becomes difficult to justify a diesel engine via CO2/fuel savings outside of tax advantages (this doesn't apply to lorries).

Gasoline is much easier on your health.

Its not the ignition (if I ran a diesel engine with CH4 I'd get no particulate emissions), or even the type of fuel (if I burn diesel in an appropriate furnace I can eliminate most soot).

It's burning diesel in a diesel engine that's the problem.

Diesel is thick and has a low vapor pressure. When it is injected, therefore, it is more akin to tiny droplets of fuel whose surface burns. Eventually there is -locally- no air around the droplet and the droplet pyrolizes and becomes a particle of soot.

Ironically, diesel engines run very lean (excess O2). But in the neighborhood around the droplet, without good mixing, you get low concentrations of O2.

Gasoline has a low vapor pressure, so it is essentially a gas, not a droplet in the combustion chamber. Therefore there is a flame front across a fairly homogeneous mixtures of gases and there isn't a local lack of O2 (assuming the air ratio is right).

For a gasoline engine this breaks down in two scenarios: Cold engines and direct fuel injection:

- In a cold engine the T might not be high enough to vaporize the fuel and the engine won't start. Therefore more fuel is used and it is in the form of droplets. This is what the choke is for in carburated engines, and now the computer does the same.

- In a direct injection engine there might not be enough time to vaporize the fuel. High P are used (and to shove the fuel into a high P chamber) to encourage vaporization. But its not as effective as port injection.

Direct fuel injection, however, allows for leaner fuel mixtures and more control of the burn (higher compression ratio) so it's basically necessary to achieve efficiency standards.

Another feature/problem of diesel is their high compression ratio. This is how the diesel cycle is more efficient than the Otto cycle (otherwise, the Otto cycle - all else being equal - is more efficient). However, high compression ratios imply high NOx emissions (NOx is an endothermic reaction that lowers P -> high T and high P favor its formation).

So you can see that environmental goals in ICE work against each other. Lowering CO2, or rising fuel efficiency, means rising NOx or soot emissions (or finding a way to shift the curve). You need a transformative technology to improve NOx, soot and CO2 (like fuel injection in the 80s).

In F1, there are no emission rules engines don't have to last 300 000 km but there is a very strict efficiency rule. Here Mercedes claims to have achieved 50% thermal efficiency, which is insane for a small ICE running at 10k rpm and producing 500hp/L. A typical gasoline car gets at best 25~30% in its most efficient state.

Encouraged primarily because of its lower CO2 emissions bang for buck. Its why I bought a diesel car. The latest one with a 2016 engine performs rather well in terms of particulates, thanks to the mandatory AdBlu system.

I remember hearing that Mrs Thatcher queried this asking why lean burn petrol wasn't being considered.

Mrs T had a background in chemistry

That "article" is beyond worthless.

European cities are usually worse than American cities for many measures of air pollution because the streets are more tightly packed, which means less ability for the pollutants to disperse. Housing and pavements for walking also tend to be closer to roads. On the other hand, the highest levels of pollution are usually experienced by drivers, because they’re sitting closest to the sources of pollution, in the flow of traffic and in effect just behind the exhaust of the preceding car. So it may be that pollution levels averaged over a city are not an accurate reflection of the health impacts on individuals, or on certain subsets of individuals. You’re much more likely to be walking in London compared to most American cities, rather than driving, but you’re also more likely to be living right next to a road with a lot of traffic. Either way, air pollution in London is a problem that has to be tackled, but it’s not going to be that easy to directly compare different cities.

I've got one of those!

At risk of sounding like a commercial, you should get a Levoit HEPA purifier. It'll clear that right up.

The rate of taxi replacement for old diesels is currently doubled, with the lifetime of a (Euro 3, 4, 5) diesel taxi reducing from 15 to 12 years over the years until 2022, so each year two years worth of old taxis will be too old and replaced by ZEVs or other low emission vehicles.

Yes, they're a big polluter, but they're also moving a LOT of people around the city, so that sort of cancels out. If anything the taxi drivers remain annoyed that this means they're going to be buying a (very expensive even after grants) new taxi sooner than expected.

The Mayor spent about £25M basically bribing those in younger taxis to upgrade to ZEV anyway, paying them over £10 000 each in some cases to swap from an old diesel (which would then either be scrapped or sold outside London since it can't hit criteria to be newly licensed as a London taxi now) to a PHEV.

I guess you mean the ubiquitous Vespas (and other scooters)? I had the same experience with Barcelona. Yeah, a transition to electric scooters would definitely improve the air quality (and also the level of noise pollution) in many Southern European cities...

Seattle had horrible air quality problems for the past two years, because of the wildfires burning in Washington and BC.

Usually, winds carry that smoke into Idaho, but due to abnormal weather patterns, all that smoke was carried into Seattle and Vancouver.

What do you mean “no options”? It’s possible to buy American, Japanese or even Chinese cars in Europe. Regarding the norms, nothing prevents the manufacturers from building cars exceeding the minimum norms.

Edit: it’s also possible to buy a non-diesel car. New petrol cars are actually cheaper than diesel. There are plenty of EVs available on the market. Heck, even hydrogen, if one really wants to.

I'm not sure, but I was curious as well. I have a 2011 X5 3.5d that has SCR and uses DEF fluid. I googled around a bit, wondering if pm2.5 was reduced using DEF, or whether the DEF was for other pollutants. I'm not sure how clean it is relative to gasoline engines in terms of particulate matter, but obviously it's better than without it.

Of course, much of the fleet in London will be older. It was shocking to me to see (in the article) how diesel vehicles had gone from 1.x million in the 90s to 12+million today.

we do have emission rules and the article is very dramatic. (here's an interactive overview that gives some idea https://waqi.info/)

The air in London from my own experience is not great but it's also not much worse than in many other large cities, and it has definitely improved a lot over the last decade or two.

Other European cities at least in my experience are completely fine. I've not noticed anything that sets Berlin or Stockholm apart from American cities, definitely not to the point that'd be a reason for me to move.

Electric winning in 1910s would have been worse. Batteries were made of lead acid, and electricity was generated from coal plants located inside of cities, without even any scrubbers. Coal burning releases heavy metals.

Pollution deaths would've been sky high if electric cars "won" in 1910.

How do you plan on manufacturing that ethanol?

The difference in CO2 is marginal. Petrol produces about 10% less CO2 / km than diesel at the same fuel-efficiency levels while diesel engines have about 20% better fuel economy than a similarly-sized petrol engine.

Of course, the petrol version will make quite a bit more power as well. When you look at CO2 per HP, the differences are negligible.

Perhaps, but not because of air pollution. We didn't stupidly jump on the diesel bandwagon.

The real answer is to get rid of fossil fuel powered cars - gasoline or diesel.

The article talks about NOx. Do brakes and tyres produce that?

Direct injection petrol engines are now fitted with particulate filters in Europe.

Particulate matter is about 60%-20%-20% between engine, brakes and tyres. Electric cars eliminate the emissions from the engine, greatly reduce the brake emissions because of regenerative braking, and slightly increase tyre emissions because of increased weight. And of course Nitrogen dioxide is eliminated by electric cars. Overall you’re taking about a 100% reduction in NO2, and a 70%ish reduction in particulates.

One other point also is that tyre particulate emissions vary hugely according to composition and manufacture. So we will need both a switch to electric and proper regulation of tyres, then we’ll really be getting somewhere.

Euro 6d now and previously Euro 6d Temp already forced direct injection to have a filter.

The paper about brake and tire wear you cited receive a Corrigendum about false attribution and conflict of interest because the author works in a motor tech:

The authors regret that as Victor Timmers did not carry out the research under the auspices of the University of Edinburgh, nor in collaboration or consultation with any personnel at the University of Edinburgh, the affiliation of “University of Edinburgh” has now been removed from this work at the request of the Institution. In addition, subsequent to the publication of the Paper, Victor Timmers has disclosed a potential Conflict of Interest with regard to the work, namely: “non-financial support from Innas B.V, during the conduct of the study”.

The authors would like to apologise for any inconvenience caused.