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Decades of diesel use in Europe have created a public health crisis (bloomberg.com)
181 points by pseudolus 7 days ago | hide | past | web | favorite | 179 comments

If you look at the actual data over the last 25 years, it's clear that London's air quality has steadily improved over time: https://www.londonair.org.uk/london/asp/advgraphssiteplot.as...

There are particularly large decreases in Sulphur Dioxide and Carbon Monoxide - the former due to reduced sulphur in fuel, and the latter due to catalytic converters. But pretty much all the other metrics have continued to improve too. Having worked in Bloomsbury for 30 years, I can definitely tell it's got better.

But it's not good enough. When City Hall is hailing that air quality is actually legal for the first time in ten years, that's both good and comical at the same time. https://www.bbc.co.uk/news/uk-england-london-42681113

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. Certainly I have less problem with allergies in London than I had in Berkeley. This should in no way excuse London, but you have to get things in perspective.

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.

Yes - it’s local to the point that air quality can vary significantly within a matter of feet along large or congested roads and walking closer to buildings/further from the road in these areas is a surprisingly simple thing you can do to improve the quality of air you breath.

Or indoors, for that matter. It's very easy for a house to reach 50 to 100 on an AQM meter, which isn't going to be immediately noticeable, but which very well could have long-term consequences.

A good HEPA filter will take care of that. As a bonus, if you're allergic, you'll get rid of most of the pollen that way.

To add to this, cumulative improvements in air quality over time don't mean squat if your current levels are still considered harmful.

If you reduce your exposure to lead by 50% annually and you're still well above the safe exposure limit, you might be making progress and still not having positive impacts on health.

There isn't a magical threshold where things flip from "harmful" to "not harmful" and it doesn't matter how far above the harmful line you are. Reducing your exposure to lead by 50% annually will have big positive health impacts even if it's still too high.

Actually there are limits for how much lead is considered harmful in your system. OSHA has exposure limits that indicate amounts per hour, and those amounts decrease the longer you're exposed. It takes a long time for lead to leave your system and prolonged exposure at levels higher than your system can process will result in a net gain or build up.

If you're above the acceptable limit, and you don't reduce exposure to below that limit, then there's no benefit.

OSHA picking an acceptable limit does not mean that the harm when below that limit is zero, or that harm does not increase as you go higher above that limit. Being exposed to ten times the limit is worse than being exposed to twice the limit.

>>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:


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

I’ve lived in London for 15 years and I’ve never experienced that. I suspect it’s something of an urban myth.

Happens to me! It's mostly the tube I think though - airborne brake residue etc, is what I've been told.

Me too, in the tube – definitely not a myth. A friend even got his white dress shirt ruined by the stuff.

That’s credible - it could be quite localised on the tube to certain stations or lines if that is the case - I’ve noticed that I get black marks all over my hands occasionally from the escalator handrail in some stations but it’s only a small minority of the ones I’ve been to.

Damn, how much would it cost to just run some air filters down there?

'merican here with normal snot; when I'm doing stuff (house fixy stuff) that turns my mucous colors, it's my sign that I need to go grab a dust mask. Is this not really a concern down there in the underground because $REASONS, or one of those "umm, never thought about it, but now that you mention it..." things?

It's more: this is how we have to get to work so go back to your book :D

Beijing and Shenzhen both made my snot go black when I was there sourcing LED components.

Used to happen to me in New York 15 years ago. Hasn't happened since, though.

Happened to me systematically in Wuhan, a few times (but much less) in Shanghai

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

As someone who made the opposite move (Bay Area -> London) I found that I started suffering from hay fever for the first time in my life.

I think that any move to an area with a sufficiently different mix of pollen can cause problems for your immune system.

Some years ago I moved from northern Norway to central Dublin. By any reckoning that's a decrease in air quality -- though Dublin is still much better than most cities -- but it also came with a reduction in allergic reactions.

I suspect simply because there isn't as much nature in the vicinity, which I don't actually appreciate. Oh well.

As someone who has always lived in London, I started getting hayfever around age 22. When asked by doctors if I have any allergies, and I say nothing except maybe hayfever, they always say "oh everyone has hayfever"

Its commonly not allergy e.g. not a histamine response. It can be simple irritation due to particulates in the air. Everybody should respond to that.

Pollen could definitely be a key part of it, but I doubt it's the whole story. Checking the PM 2.5 count for yesterday for the Bloomsbury sensor in central London, it's actually about 70% of that at any of the sensors in the East Bay (Berkeley, Oakland, etc) or San Francisco.


You need to convert units, because the US readings are given on the AQI scale, whereas the London ones are raw measurements:


Especially in the Bay Area. There's a reason sour dough bread is a thing, for example. It's in the air.

Wild yeast is in the air everywhere. Sourdough is a thing in SF not because the environment there is particularly good for it, but because of historical reasons (ie, French bakers moving in during the gold rush).

>Wild yeast is in the air everywhere

But not the same yeast everywhere. Plus bacteria are also a factor, and also vary place to place. Some may cause worse allergies than others, depending on the person.

As far as I know, French bakers didn't bring the yeast (or starter) responsible for sourdough. They just brought french bread. The sourdough part happened naturally, at least initially. Now it's actively encouraged.

But even with the right starter, the further east you go, the harder good sourdough is to make.

> 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?

The bay area has a lot of grass and pollen producing trees. And also mold spores in the rainy season. South bay has a lot of grass. Berkeley has a lot of tree pollen. San Francisco tends to have issues with mold spores.

I'm allergic to grass but not tree pollen or mold spores.

I’m sure the air quality isn’t great in London, but this article is a hodgepodge of anecdotes and pollution stats.

But no actual facts about the claimed crisis. Not a single statistic about how people are affected. No documentation of the existence of a crisis, much less documentation of the claim that said crisis is caused by diesel in particular (rather than just air pollution in general).

Would be nice if the author had spent some time finding some facts instead of making everyone dumber with a sensational headline without a factual basis.

On the plus side:

In the Netherlands, more electric cars were registered this year than diesel cars.


This is actually a side effect of the Dutch government reducing business ownership subsidies (bijtelling reduction) next year, but it's still a positive effect, and very welcome in car congested Netherlands where many people live quite close to major roads.

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..

Not surprising considering how heavily taxed non-EVs are in Norway.

You say that like it's a bad thing.

No, it was an unemotional reply.

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.

Like most complex systems, the solutions need to be applied in as many places as possible. Reducing car journeys, combined with cleaner vehicles, is all going in the right direction.

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

I guess you mean the price at the pump?

Can't say I've noticed because I try to drive our diesel as little as possible. The difference in road tax between diesel and benzine is pretty large though. I can't wait to get rid of our diesel car.

Yeah, the difference between the two fuel types that pumps advertise is tiny. Only three years ago we hit a low of .95 eur diesel / 1.50 eur gas; just this afternoon it was 1.31 versus 1.61!

Some parts of the world are still living in conditions resembling the Great Smog of London, only it doesn't go away after a while, but stays for years.

For example, the daily average pollution levels across all particulates being tracked in my city (PM 2.5/10, CO, SO2, NOx, and some others) have been several times that of the highest levels on the dirtiest day in London's history for the last 10 years.

If we compare, say, our daily averages taken on the dirtiest ~1/3 days in a year to the most polluted day in London's recent history, the ratio goes to something like 10-200x, depending on pollutant.


You'll never see it mentioned in big news outlets though. Who would give a damn? It's certainly not London.

It is mentioned though:



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.

Sorry, I should have been more clear in my whining. The largest cities are being talked about, be they located in Europe or Asia. It's the smaller ones who suffer the most and whose population has zero hope for any progress (or simply doesn't care).

Beijing is a health resort compared to where I am located. At least my friend claims so (he spent about 3 months there on a business trip back in 2011.)

I know of at least 3 cities in my country suffering from extreme air pollution. You won't find any news articles about any of them.

If you don’t mind me asking, which country are you in?

Sure, I am from Kazakhstan. The same situation can be found in pretty much every country in the region though.

I plan to take a lot of pictures during the upcoming winter, because almost no one on the English-speaking segment of internet believes that there can be so much pollution in the air, that it reduces visibility to 10 meters.

Any light you can shed on this (pun intended, of course) is welcome. Still, sounds incredible, is it just on peak times or on a daily basis?

In winter time, almost every evening, from 6:00 PM through the night. Except for windy days (from ~7 m/s upwards), which are pretty rare.

It's all because of the old Soviet heavy industry which hasn't been properly maintained since 1991 (say what you want about USSR, but there was more responsibility then), crappy gasoline, lots of old cars which made their first 100k miles in Germany or US, high sulfur coal being used in stoves... the whole shebang.

Did I mention that some people use cow dung/rubber/plastic rubbish in their stoves?

Yep, we're living on the same planet as you are.

It sounds terrible, I feel truly sorry anyone has to live with so much air pollution. You're right I haven't seen any coverage of Kazakhstan in the media I read.

Are you still using mazut as well?

Not the person you were asking, but I did a double take on your question because I had thought growing up in the DRC that "mazut" was the French word for diesel. Turns out mazut is a separate thing. Also, it was definitely used in the local heavy trucks up to the last time I was there in 2011 - ones like this: https://farm6.staticflickr.com/5292/5509628757_f8219820b9_z....

> Unfortunately governments around the world aren't often leaping to take effective action.

This is a widespread issue. We are heavily dependent on the Government on almost every issue, and people seem to want to be more dependent on them. But the question is, what can we do about it that would be effective when we are getting pressure from all fronts because of misplaced power, and financial incentives?

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.

A lot of pollution isn't visible to the naked eye. PM 2.5 particulate emissions are so small that you can't see them.

> 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.

>For decades, Europe will be united by filthy air and a slowly unfolding public-health crisis caused by its embrace of diesel—something that was supposed to heal the environment.

More than a bit hyped, there is a lot of Europe outside London (and outside other European major cities).

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

The air quality in Berlin is simply the best among all the cities I’ve lived in.

It depends on the street/proximity to a park or a major road. You are probably living in a good area.

In my experience Berlin has much better air quality than London.

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

Somewhat related: Fine particles (PM2.5) pollution in subway stations can be 30 times higher than in the urban roadside air above ground.


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

I don't why but this kind of reporting really bothers me.

I understand that putting a face on a news story makes it more meaningful. But it just screams anecdotal evidence to me.

Who cares what "one American" did?? Is the air in London bad? Then report it. And don't try to prove it by saying one person has moved.

Also, pollution is most definitely a first world problem, not third world like the writer somehow believed.

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

It hits close to home when I'm reading that article and realise that I've lived walking distance from the author.

My lungs have certainly become a lot more sensitive these days.

Pollution is something that becomes part of your day to day life, you just don't notice it.

I tried cycling with a FFP3 dust mask recently and it was shocking to me how much better it felt.

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

The article doesn't really explain the difference in health risks between diesel and gasoline. Would an American city with comparable traffic have cleaner air due to gasoline use? Gasoline exhaust certainly doesn't smell as awful as diesel, but that doesn't necessarily mean its easier on your health.

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).

> probably a racist cyclist even emits PM2.5 though nothing like a diesel truck. So this isn't a problem we can entirely solve

Oh man i hate those racist cyclists :P

Hmm, maybe an auto-correct error or maybe while editing I thought I'd written "racing cycling" and corrected to "racing cyclist" but actually I'd written "racing cyclist" and the change gave us this error.

So yes, whether racist or not, and indeed even if using some less conventional wheeled transport like a skateboard or shopping trolley - all fast wheeled travel creates PM2.5 pollution and we just have to suck it up. I presume maglev doesn't do this, but maglev isn't exactly at the top of the list of cheap inner city transit options.

I've done this many times, where it's not actually autocorrect directly in error... it's me choosing the incorrect suggestion from autocorrect because the correct suggestion is absent _and_ i've not looked carefully enough. Probably so common because we tend to identify words by shape, so if the shape matches we pick it.

Also, during a transition period, before particle filters came generally in use, a few manufacturers burned the exhausts at high temperatures in order to reduce particle size and to pass tests. These nano particles become irreversibly embedded in lung and heart tissue and even pass the blood/brain barrier. Where I live, the percentage of diesel engines was pushed over 50% by a "green" engines campaign during these critical years. We're going to find out, what this may mean in terms of long term health implications.

It's also worth noting that the reason to prefer diesel over gasoline is fuel efficiency. Diesel engines are more efficient than gasoline ones. Engines that run hotter are also more efficient - but the hotter your engine runs, the more NOx it produces.

Catalytic converter a pull most of the NOx out of a gasoline engine's exhaust, but don't work on diesels. Urea traps are an alternative, but an expensive one.

Modern Diesels have some other tech to help lower the NOx levels (like EGR and SCR systems) but the main problems are that older cars didn't have such systems, plus, for many years, VW lied and faked data, partly to avoid having to implement SCR (saving thousands per car, and the re-engineering) and partly to say the cars were cleaner than they were.

Moden SCR systems (they inject DEF, aka, urea, into the exhaust) do a really good job getting rid of NOx.

Pardon me if I don't believe what the auto industry is feeding us.

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.

All new diesel cars sold in Europe must have urea injection, EGR and particulate filters (I don't know if the law mandates the actual technologies, but those are the thing you must have to meet the pollution limits). They will allow you to drive only a few kilometers when you run out of urea, basically you are forced to drive to the petrol station to fill it up.

In a few years those "clean" diesel cars will be sold on the used market in Eastern Europe / Africa / Middle East. At which point the new owners will disable all the pollution control systems to eliminate maintenance hassles.

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).

Where I live, and I believe many other European countries as well, diesel is about 5-10% cheaper than gasoline (due to less tax). OTOH there's a yearly fixed tax for diesel cars (some hundreds of EUR).

So the intent at least originally was to discourage the plebs from buying diesel cars, whereas those that used a lot like trucks, taxis etc. got cheaper fuel (for them the fixed yearly tax was a trivial cost compared to the advantage of cheaper fuel and a more efficient engine).

I agree this is a mistake that should be rectified, but it is of course politically very difficult.

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.

Sure, if money is not an issue, you can do a lot better.

Look at, say, WWII airplane engines. They had 4 sodium cooled valves per cylinders, overhead camshafts, power density around 50 kW/L, pretty darn good bsfc, all this decades before anything like that appeared in civilian cars.

Well that's the point. Engineering is as much about compromise as it is about anything else.

A great comment - detailed, comprehensive and correct. Thank you, erfgefesa.

Thank you for this very detailed explanation !

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

The Kings College sensor data is visualised on this page: https://www.londonair.org.uk/LondonAir/nowcast.aspx

When I used to cycle in London I noticed that I struggled to recover at traffic lights. On one occasion I thought "this is it" because I simply could not catch my breath whilst my HR spiked. Most unpleasant.

In spite of its known properties, diesel use was encouraged by Sir David King, the chief UK scientific adviser from 2000 to 2007.

https://en.wikipedia.org/wiki/Diesel_exhaust None of this was new. "Diesel exhausts, long known for their characteristic smells".

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.

And the massive tax advantages

Ecouraged by tax reductions in the service of CO2 efficiency.

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

Mrs T had a background in chemistry

Petrol emissions are a trade off. Reducing cold start emissions requires a catalytic converter, but they melt if you run too lean. So vehicles actually run richer than required (or efficient) to shrink those first 5 minutes of emissions.

:roll eyes:

Most european car rides are perhaps under 15 minutes, so...

Isn't this a general problem for large cities? A quick glance at Google gave me [1], indicating that this isn't a problem limited to London.

[1] - https://www.cbsnews.com/pictures/top-10-smoggiest-cities-in-...

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.

If you have a nice car, you likely have the windows shut, and the AC/heat on, set to recirculate, and the air is filtered through a HEPA filter.

Meanwhile I'm on my bike, breathing all the fumes with no protection whatsoever.

That "article" is beyond worthless.

There are now affordable devices available to monitor air quality at home. I've recently bought one [1] that measures PM2.5, CO2 and tVOC amongst other things. It's quite interesting to see spikes in particulate matter after crop harvesting or in certain weather conditions and determine if there's an apparent relation to difficulty of breathing.

[1] https://cleargrass.com/air_monitor/overview (Website in Chinese only, unfortunately. The device can be set to english though.)

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.

I'm too paranoid to even connect the air monitor to the internet, so letting it talk to other appliances is out of the question for now. :) But it's good to know that HEPA filters are so effective against fine particles. I'll have to check that out. Thanks!

Oh, Levoit's purifiers do nothing like that; they're pure mechanical devices. A high-static-pressure fan, a stack of filters, and some plastic, with a minimal amount of electronics for dead reckoning status LEDs.

I just meant it'd clean your air. ;)

The air quality in Westminster this week is excellent. :)

Yet somehow the taxis are not being replaced at nearly a fast enough rate. These are surely one of the major polluters but they seem to have politically captured the entire mayorality so there's never much complaint about them and the avoid the ULEZ charges etc.

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.

> Yes, they're a big polluter, but they're also moving a LOT of people around the city, so that sort of cancels out

How does that cancel out? It seems that it is a force multiplier.

that's not nearly fast enough though. go stand outside the Kings Cross taxi rank and you're nearly floored from the fumes.

The last European city I spent much time on the streets of was Palermo, Sicily around six years ago. The air was offensively bad during commute times in the city center, and it seemed mostly caused by 2-stroke vehicles if memory serves.

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...

In 2014, in Chegdu, China, there were converted electrical scooters (the bike scooter, not the standing roller) everywhere. Quiet, efficient, no smell. It was miraculous.

I'd really like to see that happen in the West, but there are some rather idiotic people around who thinks the sound - like grinding metal with a chainsaw - is part of the fun.

It should also be noted that as of 2015, the average age of a passenger car in use in Europe is 10.7 years, with a mode of around 12 years, and max 17+ years. Out of a fleet of 252 mln, 123 mln or about 50% were 10+ years old in 2015.

Same for light commercial vehicles, and even worse - at 11.7 years average - for mid and heavy commercial vehicles.

See page 9, 10 & 11 here: https://www.acea.be/uploads/statistic_documents/ACEA_Report_...

Londoner with a diesel car (2016 Ford that is ULEZ compliant), here:

London's air is far, far cleaner than many other cities around the World. I was in Paris last weekend, and I think that's more polluted because congestion seems much worse in a much larger area than it does in London.

That does not mean it is clean or safe, however, there are challenges:

As the article points out, for many years the government pushed diesel, so there are a lot of cars out there. They have advantages that make them attractive to a lot of people (myself included), so if they're ULEZ compliant, we'll buy them in part because the turnaround has made them cheaper on the second hand market. Fleets of German cars are being bought, depreciated and sold at knock-down prices.

Go to the biggest 2nd hand dealer in London (Cargiant), go to the Merc and BMW hangar, and find me a petrol car: you'll be hard pushed, and when you do find them, they're more expensive.

Electric is also not a viable option for the vast majority of Londoners. Where I live (TW1), we're way outside central London, in Zone 4. Even here, off-road parking is very much a rarity and exception.

The local council (Richmond) has thrown money at lampost charging stations, and is installing around 250 of them across the borough. A borough of 195k people are going to share 250 charging points. This is absurdly low.

What about public transport? It's true, London is one of the best public transport cities in the World. I use the bus frequnetly, often to get to my nearest tube (a 45 minute walk away), or use the train.

However, it's also expensive, and for most people driving - even with the ULEZ and congestion charges - can make more financial sense.

It's interesting as well that the article calls out Marylebone Road and Hyde Park corner as the most polluted spots.

Marylebone road is party to 4 major train stations: Marylebone, Euston, Kings Cross and St Pancras International. Almost anybody trying to make a train journey to the North of London or to avoid using a plane to get to Europe is going to travel along Marylebone road. It's taking one for the team: those taxis and cars are normally carrying people to get to those stations.

They're well served by public transport, but heavy bags and suitcases on the London transport system is fractured: it prompts us to use cars instead. I did this myself just this weekend when getting to and from St Pancras for the Eurostar, because the alternatives were utterly draining.

And as for Hyde Park corner, well it's a central crossing point for many routes out to the South, West and North of London and its centre. The alternative would be to build ring roads that were once planned, but would turn London into a motorway-centric city like Birmingham, which would just encourage more driving.

Diesels need to get more expensive to own, electric needs to get easier to own for those of us without driveways, public transport needs to get cheaper, and the concentration of rail terminuses into a mile long stretch of road needs rethinking long term (it's going to get worse with HS2).

But at the same time, we have it way better than many other cities.

They moved back to Seattle right on time when it went up to become one of the most polluted cities in the US[0].

[0]: https://www.lung.org/local-content/_content-items/about-us/m...

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.

Somehow we can thank german car makers, which through the eu have imposed the so called “euro” emissions “standards” that have 0 health benefits and non eu made vehicles are taxed to death. Europe is filled with cars made in that country that have been polluting for decades and consumers dont really have options.

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.

In response to your edit: Petrol cars have always been cheaper than diesel ones to buy in the UK. They cost more to service too. Usually you have to be doing well in excess of 15-20,000 miles a year to make the extra expense worth it.

Also, doing low mileage in a modern diesel can cause issues because it doesn't get the opertunity to run the cycle that will burn the crap out of the particulate filter.

Hence diesel is so popular as fleet cars.

At the moment, my Dad gets a company car though and the Tesla Model 3 just popped up as an option on their portal. He and serveral of his colleagues are in the process of swapping.

My Dad does about 20,000 miles a year for work.

This is not widely known I think but there are significant tax advantages now available in the UK for low emissions/electric cars provided as a benefit in kind/through salary sacrifice schemes even where the car gets no business use at all.

It makes sense when the distances to travel are not long and even more sense for the fleet operators. The maintenance costs are so much lower.

You can buy them as long as they are built in europe.

Edit: a quick look at mobile.de will show you diesel is cheaper than petrol.

Second hand. Because they have higher mileage and because of the government push to remove Euro 4 and Euro 5 from the roads. So obviously people try to flog them left and right. There just tons of it on the market.

What do you mean “as long as they are built in Europe”. Are Teslas built in Europe? No.

Erm teslas are taxed in the eu. Not to mention conspiracy theories around how “bad electric” cars are.

Of course Teslas are taxed in the EU. Like any other car, even the ones manufactured in Europe. Or European cars in the US. I'm not sure what you are getting at.

"Presently, the EU imposes import taxes of about 10% on cars entering from the United States. This additional tax, which comes on top of the VAT that car buyers have to pay when purchasing a vehicle, has become an unnecessary handicap for companies like Tesla, whose cars become more expensive compared to local offerings."

The tariffs. Yes, indeed. A response to the US 25% tariffs on European light trucks. The Chicken Tax :)

Do European countries not have emissions rules for their vehicles like we do here in the US? (California to be specific) The diesels here have to use a DEF solution to remove NOx emissions from them. In California, your vehicle has to pass a smog emissions test in order to be able to drive it.

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.

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.

Maybe this will start encouraging politicians to re-think city planning and transportation. Maybe they would go as far as banning diesel all together as well as creating pedestrian zones. Electric scouters are currently banned so they could overturn that.

More, and more interesting air quality data:


This is a pity. It's sad that big oil won the ethanol/gasoline war, otherwise we could all be driving clean-burning high-revving cars.

Even bigger pity that electric didn't win in the 1910s.

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?

Sure but using diesel saved carbon emissions as its more efficient than petrol. Surely that makes it worth it?

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.


Would you please stop breaking the site guidelines? This comment wasn't substantive to begin with, and the part about downvoting and "triggered" is not acceptable. Then you perpetuated a flamewar and broke the guidelines repeatedly below.

We've had to ask you many times not to do this. Eventually we will ban you for it, so please just refrain, regardless of how right you are about diesel.


I didn't downvote you, in fact I read your comment after your edit. You are complaining exactly about behavior you yourself just did: you made an assertion and didn't explain in what way or cite sources, simply "diesel saved millions."
ThomPete 7 days ago [flagged]

I didn't know I had to point out something that obvious and when asked I actually answered.

And guess what, when I actually answered I was downvoted for that too.

Here is the thing: to you it is incredibly obvious. Despite the clear feedback that other people don't agree, you still insist it is incredibly obvious. To some people it is incredibly obvious that AGW is real; to other people it is incredibly obvious that AGW is a scam.

Just asserting it doesn't advance the conversation, and copping an attitude about something so meaningless as karma points is ridiculous.

How have they saved millions of lives?

How many people do you think where brought to hospitals. What do you think the machines that build the hospitals were used for? How do you think we build damns, roads, buildings, how do you think power generators work and I could go on. Expand that to fossil fuels in general (medicine, concrete, asphalt, pesticides and thousands of other products)

Blaming diesel for a public health crisis is like blaming the sun for melanomas or the wind for wrecked ships.

Yes using diesel has consequences just as fossil fuels does but the upside of them far outweighs the downside and not using it would be far worse.

Not really the same as the sun and the wind. We can certainly use other fuels; its simply a choice.

Of course it's the same

Things can have both positive and negative properties. Diesel is no exception and has certainly saved more people than it killed.

Its facetious to compare forces of nature that we have to live with, to a simple choice of fuels that we don't.

Diesel is ... cheap that's about it. Everything else about it, is a negative.

ThomPete 7 days ago [flagged]

If you actually read what I wrote you would know that's not what I did.

I already gave you just some of the positive effects of using Diesel luckily everyone can read for themselves.

Likewise, reading what I wrote would reveal, I don't regard Diesel as inevitable as the sun and the wind. That was a disingenuous comparison.

That's all on this subject.

ThomPete 7 days ago [flagged]

Nice strawman. I didn't claim it was. So yeah you kind of exposed everything about your intentions here. Thanks for that.

"Blaming diesel for a public health crisis is like blaming the sun for melanomas or the wind for wrecked ships."

Putting diesel in the category of 'sun' or 'wind' is pretty clear I think.

Then you should think it through some more.

The point is that it's absurd to only look at the negatives. Just like you wouldn't only be judging wind or the sun on negatives you can't only look at the negatives only of diesel you have to look at the positives and THEN decide whether it's worth it.

Perhaps others could attempt to be more clear, if they didn't mean what they actually wrote.

How is that related to diesel vs petrol?

Why would using petrol be "far worse"?

Well if you care about CO2 petrol is more than that.

And if you care about NOx and other pollutants diesel is more than that, which is what the article is about.

It's about a public health risk. Which needs to be contracted by how many lives it saved. Thats the only way to look at this if you want to assess whether it was a good or bad idea in the first place.

"One American decided to move home to spare his family."

Oh the irony. This tones sounds like FUD quite a lot.

The overall mortality rate in US is much higher.

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

He was lucky with his first summer. 2019 had fewer wildfires than 2018, and 2017 was even worse:

"On September 5 [2017], ash from the Central Washington fires fell "like snow" on Seattle and as far west as Grays Harbor County which borders the Pacific Ocean. University of Washington meteorology professor Cliff Mass said the situation in Seattle with "a smoke cloud so dense one would think it is low stratus deck" was unprecedented in his 30 years of experience."

https://en.wikipedia.org/wiki/2018_Washington_wildfires https://www.iii.org/fact-statistic/facts-statistics-wildfire...

I was in Oregon for the eclipse in 2017 and the air quality was really terrible.

Has the anti-Diesel hysteria reached its peak yet? Some food for thought:

- gasoline direct injection engines produce much more harmful particulate matter than current diesel engines (https://en.wikipedia.org/wiki/Gasoline_direct_injection#Emis...), plus some carcinogenic gases like benzoapyrene.

- a lot of the particulate matter emitted by cars comes from brake and tire wear, which even electric cars have (https://www.greencarcongress.com/2016/04/20160418-pm10.html).

So blaming it all on Diesel engines is a bit short-sighted...

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.

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

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

Replacing them with electric cars will only solve part of the problem - see my second point above. The real answer is probably to reduce usage of cars and encourage walking, cycling and using public transportation...

Last year I bought a particular sensor (I intended it to be a science project for my son): https://nettigo.eu/products/nova-fitnes-sds011-air-quality-s...

I carried it around with me for a few days in London, commuting in by train from the suburbs. There were two places that had the highest particulate levels. The first was in my kitchen when I was cooking (no comment!), and the second was on the London Underground. Particulates were far higher on the tube than on the street in central London. So high I would have thought it was a serious health risk for tube drivers. Presumably this mostly comes from the steel wheels on steel track. I don't know whether ingesting steel particulates is more or less healthy than other particulates though. Has anyone done any studies into whether tube drivers have higher rates of health problems than overground drivers?

Edit: table 1 of this paper confirms that the particulates on the underground are mostly iron: https://assets.publishing.service.gov.uk/government/uploads/...

>Presumably this mostly comes from the steel wheels on steel track

Highly unlikely. Steel-on-steel is used because it lasts for YEARS without needing replacing due to wear.

Some of it is from that but mostly from the brake pads. You can see it collect on those cylinders between carriages.

What kind of cooking were you doing? High temp ( near smoke point) with oil is supposed to be very bad for health. Gas ramge?

Frying food seemed to be particularly bad, even with the extractor running. If it's not too cold, I open the kitchen door now when I'm frying. Burning the toast doesn't help either. And candles resulted in fairly high levels too (my wife is Danish, so candles are a big thing in our house).

If anything I'd suspect friction brakes as the source of the particles.

It's better to solve part of the problem than none of the problem. I don't use a car day to day but it's a requirement for my SO to get to work. Cars will always be a requirement for people so changing to hybrids, PHEV and fully electric is only a good thing for our health and the environment.

What's the requirement out of interest?

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

I doubt the author can pinpoint his health issues to the effects of NOx. Particulate matter can also cause asthma attacks for instance. I'm not saying that Diesel cars (and buses, trucks etc.) are not a factor in pollution, but the article is focusing solely on them and describing Seattle as a comparative paradise, which I find pretty laughable. Ok, Seattle probably has better air circulation than London, but I hope you'll agree Diesel engines can't be blamed for that ;)

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