USELESS ULEZ - Choked? Has Sadiq Khan's flagship policy saved lives, or harmed livelihoods?

Summary

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Everything Electric Podcast: "USELESS ULEZ – Choked? Has Sadiq Khan's flagship policy saved lives, or harmed livelihoods?" (July 27, 2026)

Host: Helen Czerski (for The Fully Charged Show)
Guest: Dr. Gary Fuller, Air Pollution Scientist at Imperial College London

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Overview

This episode tackles one of London’s most controversial sustainability policies: the Ultra Low Emission Zone (ULEZ). Host Helen Czerski sits down with Dr. Gary Fuller, an expert with decades of experience measuring and interpreting air pollution data in London and beyond. Together, they demystify the “invisible” world of urban air pollution, offering a deep dive into the science, the history, crucial policy interventions, and — crucially — the quantifiable effects on public health brought about by ULEZ and its predecessors.

The discussion is both informative and optimistic, with new research offering compelling evidence that such policies are not only making a difference in air quality, but are measurably saving lives.

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Key Discussion Points & Insights

1. Background: How Bad Was London’s Air?

• London’s air has dramatically improved since the 1950s “super smogs” ([04:33])

  • In the 1950s and 60s, thousands died from smog events.
  • Even in the 1970s-80s, visiting the city meant coming out smelling and seeing black soot after blowing your nose.
  • With the closure of coal-fired power stations, some improvements arrived, but by the 2010s, traffic pollution (especially diesel) had stalled progress.

• Stalled Progress Pre-ULEZ

  • Study with Anna Font (2010-2016): At the then-current rate, it would have taken London 193 years to meet legal air quality limits ([04:33]).

2. What’s Actually in London’s Air?

• Public focus is on diesel exhaust — but that’s just part of the story.

  • Traffic (especially diesel) is a major source, but there’s also:
    • Wood burning (open fires, stoves), solid fuels: Up to a fifth of particle pollution in winter ([08:32]).
    • Construction dust
    • Particles blowing in from the countryside: “Up to 40% of particle pollution in London is ammonia-based, much of it from agriculture.” ([08:32])
  • Smaller particles (PM2.5 and below): More dangerous because they penetrate deep into lungs and beyond ([10:16–10:49]).

  “Tiny particles, they can actually go beyond the lungs and translocate into other parts of the body. So that's an additional concern once they get small.” — Dr. Gary Fuller ([10:49])

• “The pollution is less black now — it’s brown.”

  • Much of what is filtered from the air in winter is brown, from wood burning, not the classic black of diesel/coal ([11:13]).

3. Measuring the Invisible: How Is Air Pollution Tracked?

• Network of monitors: Includes large, shipping-container-sized labs opposite Madame Tussauds and a wider network of smaller sensors ([11:41–12:54]).
• Challenges:
  • Pollution is often at very low concentrations (micrograms per cubic meter).
  • Some pollutants can “sublimate” away, making them hard to capture ([14:13]).

4. ULEZ & Low Emission Zones Explained

• ULEZ is just one of 300+ similar schemes across Europe ([15:20]):

  • Zones that ban or deter older, more polluting vehicles and incentivize newer, cleaner vehicles.
  • “Almost like a time machine” — accelerating vehicle fleet renewal ([15:20]).
  • London’s first Low Emission Zone (LEZ) in 2008 applied to large vehicles; ULEZ (2019) expanded that to all cars and later to the entire city from 2024.

• ULEZ's Mechanism:

  • Drastically reduced (charged or banned) the oldest, dirtiest vehicles from the city.

5. Did ULEZ Work? Evidence & Numbers

• Dramatic reduction in nitrogen dioxide (NO2) levels:

  • “I really struggle to think of something else that caused a bigger and faster change than the central London ULEZ.”

  “NO2 from traffic in central London reduced by about 39%.” ([19:13])

  • London went from being 2–3x over legal NO2 limits to (almost) meeting them.

• Particulate matter (PM2.5):

  • The initial LEZ (2008) had a big impact on particle pollution from big vehicles.
  • ULEZ (2019+) was less effective for particulates — most vehicles already had effective particulate filters by then, but NO2 was much improved ([21:25–22:16]).

  “The current ULEZ was really effective for nitrogen dioxide, because it was excluding vehicles that emitted a lot of it, but was less effective for particles because particle filters were already pretty standard.” — Dr. Gary Fuller ([24:57])

• New primary sources of particulates:

  • Not just exhaust!
    • Tyre, brake, and road wear now produce more particle pollution than exhaust pipes. ([25:37])
  • Policy is lagging far behind both in acknowledging and regulating this.

  “These wear processes… produce more particles than the exhausts of the vehicles. If you think about a vehicle driving around, its main source of particle pollution is coming from these wear processes and not from the exhaust pipe.” — Dr. Gary Fuller ([25:37])

6. Policy Gaps & What Next?

• “Whack-a-mole” approach is no longer enough:

  • Regulation targets exhausted tailpipes/power plants, but not ammonia, wood burning, tyre wear, or aircraft emissions ([27:09–30:01]).
  • Heathrow Airport is a massive, mostly ignored, source of ultra-fine particles (due to unregulated high-sulfur jet fuel) ([30:52]).

  “We're trying to manage the air pollution problems we have today in the 21st century using the science that we had in the 20th.” — Dr. Gary Fuller ([27:09])

• Gary’s wishlist:

  • Target all major sources simultaneously,
  • Tackle agricultural ammonia,
  • Focus on ultra-fine particulates,
  • Address aircraft and wood burning,
  • Respond to shifting pollution sources as vehicle technologies and behaviors evolve.

7. Public Health Impacts: The Real Prize

• Air pollution harms nearly every aspect of health:

  • Premature death, asthma, low birth weight, cancer, heart disease/stroke, and even increased dementia risk ([34:38]).

  “Air pollution is affecting us from pre-birth all the way through to the end of our lives.” — Dr. Gary Fuller ([34:38])

• New findings on health impacts of ULEZ/Low Emission Zones:

  • Systematic review (Europe): Studies found lower hospital admissions for heart disease as a result of these zones.

  • London:

    • After ULEZ, a 3% reduction in total A&E admissions; 8–9% reduction for respiratory and cardiac issues ([37:57]).
    • Robust even after accounting for the “what if nothing changed” counterfactual.

  • Bradford:

    • After adopting its own emissions zone, saw a 25% reduction in people heading to GPs for heart/respiratory consultations ([42:25]).
    • Compared to non-pollution-related GP visits, the effect was specific and real.

    “That's an astonishing reduction though. I mean, 25% is absolutely astonishing just for a single policy that isn’t actually that world-changing.” — Helen Czerski ([43:05])

    “If you think you could come up with a drug... that said, ‘I could reduce GP consultations by a quarter, or admissions by 7-9%’... the medical community would bite your hand off. But we have this at our fingertips.” — Dr. Gary Fuller ([50:10])

• Evidence base is strong but uptake slow:

  • Over 60% of all health/air pollution research has been produced in the last 20 years, but policy continues to lag ([45:47–45:49]).

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Notable Quotes & Moments

• On the sensation of breathing in London decades ago:

  “You’d go into London, come out, and you’d feel dirty... you’d blow your nose and see black soot — but now it’s a normal place.” — Helen Czerski paraphrasing Robert Llewellyn ([03:50])

• On policy impact:

  “NO2 from traffic in central London reduced by about 39%. I honestly can’t think of something else that produced such a dramatic change.” — Dr. Gary Fuller ([19:13])

• On the shifting shape of pollution:

  “The main source of particle pollution is coming from wear processes — tyre, brake, and road wear — not from exhaust pipes.” — Dr. Gary Fuller ([25:37])

• On health impacts:

  “If you think about a 9-year-old... two hen’s eggs’ worth of lung growth is missing if they live in the most polluted places.” — Dr. Gary Fuller ([34:38])

• Comparing air quality interventions to medicine:

  “If a drug could do that, we’d all be scrambling over ourselves to get it — but it’s much easier than that, potentially, if we just think about the world a bit differently.” — Helen Czerski ([50:32])

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Timestamps of Important Segments

• Improving air quality: Then & now – [04:33]
• Breakdown of pollution sources – [07:25], [08:32]
• “Invisible” dangers of small particulates (PM2.5, ultra-fines) – [10:16–10:49]
• How air pollution is measured (devices, challenges) – [11:41–14:13]
• History & global context of ULEZ/LEZ policies – [15:20], [17:38]
• Dramatic changes from ULEZ introduction – [19:13]
• Why particulates are harder to tackle now – [21:25–22:16]
• Tyre/brake/road wear as major particulate sources – [25:37]
• Why policy lags behind science (“whack-a-mole approach”) – [27:09–30:01]
• Airport & wood-burning overlooked – [30:52]
• Health impacts & new studies (London, Bradford) – [34:38], [37:57], [42:25]
• Policy vs science, public resistance – [45:03]
• Vision for a healthier, cleaner future – [46:37–47:09]
• Political inertia & the pharmaceutical analogy – [50:10–50:32]

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Tone

• Inquisitive: Helen Czerski brings curiosity and layperson relatability — “Why don’t we focus more on health?”
• Expert, measured optimism: Dr. Fuller acknowledges remaining challenges but stresses genuine, data-backed successes and opportunities.
• Accessible science and policy banter: Analogies (lung capacity and eggs, pollution color, “time machine” for vehicle fleets, “whack-a-mole” regulation).

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Summary Takeaway

ULEZ and similar policies have triggered measurable, large-scale improvements in air quality — and real, substantial gains in public health. Scientific knowledge now strongly supports expanding action beyond exhaust emissions, to tackle ammonia, ultra-fines, and emerging sources like tyre wear and aviation. With evidence mounting, the path forward is clearer than ever: decisive policy can yield the kind of life-saving benefits no pill ever could.

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Transcript

[A]

Foreign. Hello and welcome to the Everything Electric podcast. I'm Helen Chersky and this week our podcast is all about Eulas air pollution. What's in the air we breathe especially. I mean, I'm a Londoner, I walk around, cycle around the city, I am breathing air in all the time and I do think it's getting better. There's a good news story to be told. So this week, week I've been talking to Dr. Gary Fuller, who is an air pollution scientist at Imperial College London. He's done lots of other jobs in UK air quality stuff and he's been monitoring London's air for a long time now. And so he can see the stuff that the rest of us can't really see. You know, if it's really filthy, we can probably tell. But actually there's a lot of techniques now which allow really fine detail on exactly what pollution is, where and what it's doing and where it's coming from. And of course this feeds into things like the ulez, the ultra Low emissions zone, which has been controversial, even though I kind of think clean air shouldn't be controversial. But anyway, so we've had a really interesting discussion about air pollution, about ulez, about London, how air pollution works in big cities and what matters, and the health impacts of Ulez, which are really impressive. I mean, I'd heard a few of the numbers before, but the things Gary had to say about how much difference ULEZ and other schemes make are just, they're colossal. I mean, as he pointed out, if you had a medicine that reduced, you know, hospital admissions by that much, everybody would be crawling over themselves to get it. The impacts really are dramatic. So, yes, so we had a great conversation and actually left me feeling quite optimistic about the future for things like Eulers and air pollution. So. So, yes, great podcast to look forward to and before we get into it, here's a quick ad.

[B]

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[A]

Gary, hello and thank you. Thank you for joining us on the Everything Electric podcast. So I've met you quite a lot over the years in lots of different contexts. But just for the listeners and watchers who may not have met you before, just give us a little overview of what it is that you do.

[B]

Yeah. Hi Helen, thanks for asking me along. It's great to be back on the program. Having been on one of your predecessor ones. I'm an air pollution scientist at Imperial College London. I've spent over 30 years measuring air pollution, urban air pollution, most mostly in London. And I would say my research interests are on urban air pollution, how it's changing and then how it affects our health.

[A]

And how do you get into that? Because it does sound a little bit, it sort of sounds a bit depressing to work on. It's obviously really important. But how do you get started in all of that?

[B]

A long time ago. It's really weird. I've got a job that's lasted 33 years and originally I was taken in a two week position. There was an opportunity, well, there was a need for someone to help to compile a database when the London Air Quality Network was first being built and someone said to me, you know, look, you're between jobs, do you want to come and do this? So I went along for two weeks and then 33 odd years later I've managed to get a PhD, you know, an academic position. So it's worked wonderfully.

[A]

Very good. So I live in London and so I do think quite a lot about the air I'm breathing as I'm cycling and walking around. And what's interesting to me over time, and we'll get into the details of this is that I hear people say now, in fact, Robert Wellen has said it to me, he said, you know, you used to go into London and you know, you would feel, you would come out and you would feel dirty basically. And now you turn up in London and you kind of go, oh, you know, you know, it's a normal place. I don't come away feeling like I've been sullied by the filthy capital. Just on a big, in the big headline picture, is it true that air pollution's got better? And if so, how much?

[B]

By yeah, I mean air pollution in London's improved a great deal. Of course, you know, it's the 70th anniversary of the Clean Air Act. If you would go back to the 1950s and the Smogs we had then, then clearly London is far, far better than that. We don't get these PE super smogs where people can't see their feet anymore and you know what, several thousand people die because of each of these during the 1950s and 1960s. Even if you would go back when I was a kid going into London in, you know, the 1970s, 1980s, I agree with Robert's point. I used to come out feeling, you know, as though I was kind of like, sticky. If you've been into central London, you blow your nose and. Sounds a bit yuck, I know. But quite obviously you would see, you know, black soot from just the density of really poorly controlled diesel vehicles that were in the center of the capital. More recently, there's been, I suppose London's air pollution has. Well, it hit a period in the 2010s when we really weren't making any progress at all. There have been a lot of changes. In the early part of the century, power stations in and around the capital that were burning coal had largely been closed, the ones down along the Thames. That led to some improvements, but what we experienced was a worsening in traffic pollution. And we hit a point in the 2010s when really nothing was happening. It wasn't getting any better at all. With my colleague Anna Font, I did a study between London and Paris that looked at 2010 to 2016 and we looked at the rate of progress at that time and we concluded that it was going to take 193 years for London to meet the legal limits that it should have met by 2010. So we were in a pretty bad place. And then along came new initiatives such as the T charge and then the Ulez. And London has transformed it, honestly has.

[A]

We will get onto the. The you. Let's. I mean, that's, that's the. That's the bit of this that hits the headlines, isn't it? So we'll come on to that in a little bit. But just, you know, we all think of. Let's just do a little bit of what, what the pollution is. Because the thing about pollution, I find, is that it's one of those things that it's sometimes really hard to. To talk about, especially on tv, because it's kind of invisible, you know, like, unless you are snotting it out of your nose in some disgusting way. It's very. Like, if you just walk out, you can't see what it is. Right. It's invisible. So just give us a quick rundown of the types of pollution that matter in a big city like London and. And then we'll get onto how you detect them. But tell us what's there first.

[B]

Yeah, so if you step out into London, you'll be breathing air pollution from a whole variety of sources. And I think if you go and talk to the, you know, the average person in the street and, and you talk to them about air pollution, it's going to take them about 30 seconds before they point to the nearest Busy main road and then they point to diesel traffic. And that's been the story of, I suppose the last 15 to 20 years has been this real emphasis on air pollution from the exhaust pipes of vehicles and mainly from the exhaust pipes of diesel vehicles. But our cities are changing a lot and these vehicles are changing a lot as well. So now we're finding ourselves worried about, about air pollution sources that we've kind of overlooked for quite a long time. There's been quite a return to solid fuel burning in our urban areas, not just in, in London and the uk, but across Europe. And that is one of the major sources of particle pollution that is produced inside London.

[A]

That's wood burning stoves, is it?

[B]

Well, it's, it's not just stoves, but there's quite a lot of people that in London especially that are burning wood, are doing so on open fires and they're much more polluting than stoves. Stoves are polluting as well. We have to emphasize that it is wood. But also there's a certain amount of smokeless fuel being burnt as well because there's only a certain amount of wood to go around. You know, it's hard to get it. And that's leading to really quite substantial amounts, you know, perhaps as much as a fifth sometimes of the air pollute of the particle pollution that's being produced in London. Other sources within the city include stuff like combustion, sorry, construction, but a lot of our pollution, at least in terms of particle pollution. So we're talking really tiny particles you might have heard about PM2.5. So these are things smaller than about 2.5 microns that can penetrate quite deeply in your lungs and further in the body. And a lot of them come from outside the city. And some of the biggest sources for that is the countryside. And we think about the countryside as being a place that's clean and fresh and really positive. But a lot of ammonia is produced by agriculture. And so if you look at the particle pollution that you were to measure in London, they say averaged over a year. And if you were to weigh it, somewhere in the region of about 40% of that would be ammonia and around half of that would be other chemicals that can tell particles that contain ammonia. It's a really big source and I think much overlooked.

[A]

It's really worth emphasizing that bit about the size, isn't it? Because there was always, you know, we just dwelling perhaps too much on the disgusting blackness you used to get in your nose. But the big, the point is that the big bits of pollution, the really Big bits could get, get caught by things like the hairs in your nose. But the smaller things are, the further in they get, so the more insidious it is. That's kind of the, the game. So you get rid of the visible big stuff. But actually then once you start worrying about the tiny stuff, it often sounds quite a lot more concerning, I think, because, because it's, you know, this burrowing its way in

[B]

tiny particles, they can actually go beyond the lungs and translocate into other parts of the body. So that's an additional concern once they get small. Also, our pollution is less black. So it used to be diesel soot, it used to be coal soot. You blow your nose and see it. Nowadays our pollution is less black, but it's still.

[A]

So what color is it now?

[B]

A lot of it, if you think about what comes out from wood burning, for instance, is brown. Okay, if you take a filter, you know, we sample air pollution in London, you suck air through onto a filter and you know, then you can analyze it. But the filters that we have during the wintertime and weekends and wintertime, they're not black, they're generally brown. And that comes a lot from wood burning.

[A]

Amazing. Okay, well, let's come on to the measurement because I have visited that, There's a, there's a, there's a couple of studies. Well, I know, I know the, the air quality network measured in across London, but there's one particular place I've visited at least twice, which is on Marylebone. Is it on Euston Road? That's right opposite Madame Tussauds. And it's this thing, and it's really clever because I swear 99% of everybody who walks down that street doesn't see it's there. And yet when you actually look at it, it's the size of a shipping container parked on the pavement and it's got all these measurements inside it. And so I have to say my favorite one is the one that you just mentioned, which was like a little. There were these old school record turnstiles that used to be able to drop a record down. Like there was a little, you could stack them up and sort of drop them down. And there was a little thing that dropped filters. So you know, it sucked air through the filter and then it was automated. So every 12 hours it, it would sort of change the filter, but it changed it like one of those old school LP players, which I, I loved. But just talk to us about how hard it is because I mean people, you know, pollution is tiny. Why do you Need a great big thing, the size of a shipping container almost, to measure air pollution. Like, how hard is it to know to find things out about air pollution?

[B]

Yeah, it's actually the size of two shipping containers. It's amazing how many people we meet there and say, it's opposite Madame Tussauds. That's the best way to describe it. And you see people wandering up and down the pavement, just almost unable to spot it. So it is pretty big. It's so big because there's so much equipment in it. Not just equipment to measure air pollution, but, you know, we look at the traffic, we measure properties of the atmosphere as well that help us understand how the air pollution is moving around. It is hard to measure because the amounts of, say, the contaminant that we have are actually quite small. We're talking about micrograms per cubic meter in terms of, you know, the mass, concentration of particles. So that's quite difficult. Some of the particles that we try to measure as well are quite sneaky as well. And they partition between particle and vapor. So there are times when you can suck them into your machine. And because your machine tends to be a bit warmer than the outside world, the material that you've sampled can just volatilize away and you can lose it.

[A]

So it evaporates, basically.

[B]

Yeah, I suppose it more. It more sublimes rather than evaporates, you know, it sublimates. But yeah, it can go from being particles into being a gas and you can lose it. And it's really tricky to be able to measure these things.

[A]

Well, so, all right, so there isn't. There's these specific sites, there's this air quality network across London which is measuring perhaps in less. There isn't a shipping container on every corner. There are some, you know, smaller devices in lots of places. Let's come at this from the. From the policies that have made a difference. So we mentioned Ulez before, which is the thing that gets all the press and generates a lot of opinions. So could you. So just remind us all what the rules, like how the process of what the rules were as. Because there's a. There's a low. So LEZ is a low emission zone and Ulez is ultra low emission zone. So just tell us a little bit about what the rules are for the people who don't live in London. And then you've been measuring. What difference have they made?

[B]

Yeah. Maybe we should step back a little bit further and think about what these things are doing in. In principle. So what they're trying to do is to deter or ban. And they. They take different forms in different cities. Older and the most older and more polluting vehicles from an area. And favorite newer and less polluting vehicles. So they're almost like a time machine. So they're turning over the vehicle fleet faster than it would turn over anyway. So you have a newer vehicle fleet that is hopefully less polluting. So if you've been in London and seen the politics around Ulez and the mayoral election, you would think it was a new idea and you would think that London was the only place that it's been tried. But there's over 300 of these operating throughout Europe, not many in the UK. We're actually a bit behind the curve on these. They've been going now for around 20 years. I mean, the first ones were in Sweden. There was some zones tried in tunnels under the Alps where they just banned the really oldest and most polluting vehicles from using those tunnels. In London, the first zone was rolled out in 2008, and that only applied to big vehicles. So it applied to things that you probably have to have a special license to drive. Yeah. So lorries, buses, really big sort of coaches, things like that. And what that did was that did the same. It banned the. Well, it made a charge if you bought an older, more polluting vehicle in, then it's moved forward that. That's tightened over time. The Ulez came in and for the first time, it expanded this from heavy vehicles into affecting cars. It had already done taxes before, and so that kind of hit the headlines a lot more because it wasn't just the people that were operating these large vehicle fleets or companies that own delivery vehicles that were having to make changes. It was actually affecting individual drivers as they came into the city center.

[A]

So. And then. So when was the last Ulez change made? When was the most. Because it's been. It's sort of tightened up over the years. Right. And the area that it applies to has expand. So now I think there's two zones. There's a sort of inner zone and an outer zone. Is that right?

[B]

Not really. It's just one zone that covers the whole of London.

[A]

Now, I might be mixing it up with the congestion charge.

[B]

Yeah, the congestion charge only covers the. The central area. So when the ulez. So since 2008, we'd had schemes that restricted, if you like, the older, heavy polluting vehicles. And then the Ulez. Well, originally its predecessor, the T Charge, but the Ulez came along in 2019 and that applied to the rest of the vehicle fleet as well, including things like motorbikes, cars and so forth. So originally when the Ulez was bought in, it applied to just central London and then progressively it's been moved out in stages so that from 2024 it covered the whole of London. So that makes it a far more simple structure.

[A]

Okay, so the policy's gone in. There's a huge amount of debate about whether, you know, what people think about the direct, you know, the car drivers care about how it impacts them. But obviously what it's harder for us to actually see is how it's impacted the pollution itself. So what's the evidence? What does, what does the science say about the difference that Ulez has made in London? Yeah, yeah.

[B]

Well, I've been measuring air pollution in London for 30 years and I really struggle to think of something else that caused a bigger and faster change than the central London. U less it was really dramatic. As I said, we had many years through the 2000 and tens, if I can describe them as that, where air pollution in London really wasn't going anywhere. And in some cases the air pollution from traffic was actually getting worse in a few places. And we used to have this sort of quality check with our instruments when we looked at the data at the end of the year and we decided, are there any faults with the instrument? Can we trust it? So we have various algorithms and one of them was how similar was this year compared to the year before because air pollution was pretty static, it wasn't making any progress. So we were getting loads of alarms coming from our instrument, from the, our data systems that were saying this is just too low, something's changed, you know, has the instrument go wrong, gone wrong? Go out and check it. When actual fact it was just the changes that were being brought about by you, Liz. So Ulez was bought in just before COVID So it ran for the central London, ran one for, ran for about a year before COVID came along and changed the whole world. And in that time the nitrogen dioxide, and we can talk about why it was good for one pollutant and not for others. But anyway, nitrogen dioxide from traffic in central London reduced by. I think it's about 39% and I honestly can't think of something else that produced such a dramatic change. I mean, in the middle of the 2000 and tens we had limit values that we had to meet by 2010 and there were places in London that weren't even close and they were around two to three times the legal limit. And now we're in a position where, give or take a few digits, London is actually meeting those limits. And that's come in through the progressive rollout of the U Less.

[A]

So that's nitrogen dioxide. How about things like particulates and the various different sizes of particles? How was all of that affected from

[B]

the current rollout of the Ulez? It's had little impact in that, but what we're seeing, it's part of a picture that's driving these concentrations downwards. I think it's worth thinking about how these schemes work in order to understand that. So when the first low emission zone was rolled out in 2008, it had a dramatic change on particle pollution on PM2.5, not an NO2 for ULEZ, when it rolled out was the other way around. It made dramatic improvements to NO2, but not really so much change in the particle pollution.

[A]

So just. Just to clarify things, one of these is. We're talking about NO2 is the nitrogen dioxide, which is the gas.

[B]

Sorry, I shouldn't say.

[A]

And the other ones are the particles. So one of these policies affected the particles but not the gas, and the other one affected the gas but not the particles.

[B]

Yep, exactly right. And you've got to think, why is this. And all of these schemes are very specific to the location they're setting out and also to the changes in technology in our fleet. So it's the differential between the dirty vehicles that you exclude and the newer, cleaner ones you bring in. At the time that the first zone was. That came out, was implemented in 2008, there were some real exciting technologies coming into diesel vehicles to clean up their particles. So there was a big difference between the particle exhaust in the new vehicles versus the old ones. We had things like diesel particle filters. If you come across. There were just being introduced, really, and rolled out into heavy vehicles. So that was the dramatic change that happened. And it's interesting where that happened to a large degree. When we looked to try and assess the change, we found actually little change in central London, but we found quite a big change in outer London from the first zone. The reason being that most of the vehicles that were already running in central London had been upgraded before the scheme. So a lot of the buses have been upgraded. Then when we wind forward to the recent Ulez, you'll all know and everyone that listens to this podcast will remember Diesel Gate and the, you know, the. The huge problems and legal issues that surround.

[A]

It was a scandal.

[B]

Okay? It was. It was that surrounded VW and then has gone on to. Gone on to. People have gone on critically to look at other vehicle manufacturers as well, and that involves nitrogen dioxide. And the bottom line there was the vehicles, when they're driven on the road, produced a lot more nitrogen oxide. So it's a whole family of pollutants on the road than they did in the laboratory tests when they were approved. But that is where there's been a lot of improvements. Things like Euro 6 and the different iterations of that come along have really brought that down. So now we're in a position where if you implement a low emission zone, the delta, if you like, between the clean vehicles and the dirty ones, the big change is that in nitrogen dioxide. So that's why the current ULEZ was really effective for nitrogen dioxide, because it was excluding vehicles that emitted a lot of it, but was less effective for particles because particle filters were already pretty standard.

[A]

But there's an interesting thing with particles, which I'm sure I've interviewed about people about before. It might have been you, I don't remember, which is that the sources, you know, we think of particulate pollution because of soot and chimneys and things like that, we think of it as something that comes out of chimneys and exhaust pipes. But actually that is not the only source of particulate pollution. And I think, I remember there are studies suggesting that the particles from tires, so tire wear and brake wear and all those tiny things that kind of get rubbed off as cars accelerate and decelerate, that. That pollution is sort of becoming as significant as what comes out of the tailpipe. Is that. Is that right?

[B]

Yeah, it's even more than you describe. So these wear processes, I like your analogy of things that get rubbed off, but these wear processes, so brake wear, tyre wear and road wear as well, is really important now, produce more particles than the exhausts of the vehicles. So if you think about a vehicle driving around, its main source of particle pollution is coming from these wear processes and not from the exhaust pipe.

[A]

I always think that's one of these things that it gets. So there's so much about how we think about the world in that. Because. Because when I think it's the same with the word efficiency, actually, but we sort of talk about things wearing out, but we never ask where all the bits went. You know, it's just assumed that things wear out, that they somehow get thinner in the case of tires or, you know, they get holes in the bits, but nobody ever says, where did those bits go? And of course they have to go somewhere. It's not, you know, we have conservation of mass in the world. They don't Just vanish. So they disappear into the environment. But I think, you know, the worrying thing about the tyre particulates, I guess, is that they get, it's not just that they fall off and sit on the road, it's that if as a car swooshes past, they get lifted up again into the air. There's this kind of resuspension thing, right, where if you have, you know, the busy traffic or wind then lifts them up and, and then they're once again at a height that we can breathe in. So, so it is a. What, do you know what people are doing about pollution standards for tyre wear? I guess, because that's really hard to measure, isn't it?

[B]

Yeah, we're kind of, we're into new territory. I think if you, if you stand back, almost the whole history of the way in which we managed air pollution is very much a whack a mole approach. So we've just focused on one pollutant. It's captured the public's attention, it's captured the attention of politicians as well and action has been taken. So if you go back, you know, clean Air Act, 70 odd years ago, what it focused on was smoke and not sulfur. And by focusing on smoke and ignoring sulfur, we brought about the problems from acid rain over Scandinavia and Northern Europe, from our coal and oil burning that was really, you know, really damaging for the ecosystems in those areas. So the 70s, 80s, 90s, it hasn't entirely gone away. So then we focused on industrial air pollution and if you look at these times, you can see papers written by people saying, oh, look, traffic is a real problem, but it was completely ignored. Then we move on to traffic and exhaust pipes. And although people have been talking about tyre wear, brake wear, wood burning, ammonia from agriculture for a long time, still the focus of policy is focused on the exhaust pipes of vehicles. I often say, I think we're trying to manage the air pollution problems we have today in the 21st century using the science that we had in the 20th. You know, the whole policy process is a good 25 years behind what we know about the problem. This episode is brought to you by Hong Kook. The Hankook ion tyre is built exclusively for electric vehicles, engineered to deliver what EV drivers need most confident grip, quietness, energy efficiency and long mileage. As the official tyre partner of Formula E, Hank Hook proves its EV technology is at the highest level of performance and brings that same innovation to every ion tyre on the road.

[A]

So what would you do then if you, if Gary got to rule London for a day Or a week, if you were kidding. So what would you, what would you. What sort of rules would you. If you would, you know, just to improve air pollution as a whole, like. So we've made big improvements. We don't have smog. That's all great.

[B]

Yeah.

[A]

We still clearly have an air pollution problem. I guess. What would. What, what things would. Would actually. What, what. What remains to be fixed? I guess that's what I'm getting at. What is it that, that. What if you were going to look ahead rather than just play whack a mole, what are the things you would be putting in place now that would prevent problems in the future?

[B]

Yeah, I think really there's. We have to have a focus on all of the pollutants at the same time, otherwise you end up, you know, just diverting attention between this. Yeah, this whack a mole approach. Certainly we should be paying a lot more attention to sources of ammonia. We should be paying a lot more attention to really, really tiny particles that are in our air. And some of these come from the exhaust of vehicles and can leak out through the particle traps. But there are other sources which are largely unregulated. For instance, Heathrow Airport, if you want to focus on London. Heathrow Airport is sitting there just within London's perimeter and is a massive source of really tiny particles. We can measure the impacts of Heathrow in central London in terms of the

[A]

really smallest particles, just because the particles are traveling all the way from Heathrow

[B]

into central London and because aircraft are such a massive source of them. So we've done a lot to control the quality of fuels that are used on the road, particularly their sulfur content. And that hasn't happened with aviation. So their fuels really, you know, they contain all the sulfur that was in there when the crude oil was pulled out in the first place, and that leads to a lot of really tiny particle pollution.

[A]

I had just assumed that aircraft fuel would be. Would have some rules on it, does it not, then there's no sort of equivalent for unleaded petrol or whatever. There's none of that for aircraft.

[B]

There is lead actually in the petrol that's used in light aircraft and it's still used because the engines haven't really been adapted to run without leaded petrol. So leaded petrol, as you used to know from the 1990s, is still used in. In light aircraft. But it's. The main problem is, is the sulfur and it's just expensive to remove. And also there's a lot of questions that if you were to remove the sulfur from fuel, it contains certain. It helps with certain properties of aviation fuel, specifically. It's a lovely word, lubricity. So kind of how, how slippy the fuel is as it runs through the system and how much it lubricates the engine. So it's not entirely straightforward, but it's a problem we've ignored for a long time. The other one will be going back to wood burning as well. There's a huge amount of that going on in our urban areas. And it's interesting from the work that's been done by people at ucl, the greatest problems with wood burning are not likely to be in London. You know, this. We often view air pollution through a London lens in the uk, but the worst problems, wood burning, are likely to be in smaller towns throughout the UK that have easier access to, you know, woodland wood.

[A]

Yeah, that's where the trees are. Yeah, exactly. No one's going around central London chopping down trees to, to fuel their. To. To cook their dinner.

[B]

Yeah, you're, you know, 30 kilometers away in Central London from any substantial countryside, whereas if you live. I live on the south coast in Brighton, you know, I can walk into the countryside.

[A]

So. So there's this. There's this picture then of things kind of improving. The more could be done. But what about the health thing? Especially when it comes to you, Les? Cause I think this is. I mean, you know, there's this big political kerfuffle and it's all about the input problem, it's all about the upstream problem. What. What's the. What's the pain at the point where you're doing it? Someone wants to do it. We heard a lot less, I think, about the downstream outcome, which is, obviously, you know, you're doing this for a reason. And that reason isn't just so there aren't particles in the air for the sake of particles in the air, it's because they have health impacts. So just talk to us a little bit about what health impacts? I mean, there was a very famous case more than 10 years ago now where I can't remember the name of the girl who died. That's right. But it was, you know, her mum was very committed to the cause of going back and made sure the coroner put the air pollution was the cause of death. And that was the first case in UK legal history where air pollution had been declared as the specified, you know, as contributing to the death. So that is, you know, and. And she had asthma, I think, and the asthma was made worse by the really busy roads that she lived next to. So that, that's clearly extremely serious health, a health impact. But how about like, how about the rest of us more generally? You know, I, I, I live in London, I cycle through central London every day. What is all of this doing to me?

[B]

Yeah, I think if you were to go back, I often say that we're managing this problem based on what we knew in the 20th century and not in the 21st. And now we know that air pollution is affecting so much of our health. If you went back to the last century, we knew that people died earlier in more polluted places and we knew to some extent some of the diseases that they died earlier from. And there was more cases of things like asthma. Now we're learning that air pollution is affecting us from pre birth all the way through to the end of our lives. With studies from London with looking at birth weight for gestational age, so the weight of babies compared to how long they've been in pregnancy and we find that they're smaller in more polluted babies places. We have children that are growing up and we know that air pollution increases these risks of cancer. We have a study in East London where we measured, well actually mainly my colleagues, I had a small walking role, measured the lung function of children living in East London and we found that those living in more polluted places were growing smaller lungs. And the average child living in East London, this was done about just over 10 years ago. The average 9 year old living in East London was growing lungs that were about 100 milliliters smaller than they should be. So if you think of a hen's egg, that's about 50 millilitres and imagine a 9 year old in your mind, so you can think of two hen's eggs within the nine year old's chest and that's the lung growth they're missing out on if you run through into adulthood. We know that it's a factor in everything from lung cancer in non smokers through to heart disease and stroke. And most worryingly and most, and quite, really quite recently we're finding links between brain health and air pollution. So there's been strong associations between for instance air pollution and dementia. And if you think about the way that dementia affects families and you think about the huge costs that it imposes on our society and the way, yeah that affects families, I mean it's just a huge impact. If you've ever had a relative and that this is being caused by air pollution or that some of this is, then that's a really substantial change. So if you like, air pollution's affecting us in almost every disease category that you can think of, but yet the actions that we're taking are very much lagging behind.

[A]

And so when it comes to something like the Ulez, where, you know, you said there was a big sort of clear before and afterwards thing, do we. Has anyone been able to quantify the health impacts of Eulers? I mean, can we say fewer people? Do we know, reasonably, fewer people died, fewer people got dementia, is. It's a really hard thing to quantify because of course you don't have the counterfactual where you didn't do it and you follow all the same people.

[B]

It's interesting you mentioned the counterfactual. So at the time that Ulez was being pulled out, we didn't really have these studies. They have been emerging over the last few years. So there was a systematic review done that found about eight studies across Ulez type things, so low emission zones across Europe, and I think five out of eight of those found reductions in heart disease. So cases people being admitted to hospital for heart disease, you've got to say that's quite small. But one of these looked at 69 German cities. So overall we got evidence from about 70 cities. So with Ulez in place, it gave researchers an opportunity to see was this happening in London? Just over a month ago, a study was published by Rosemary Chamberlain, who's a researcher at Imperial, and she and team looked at people being admitted to hospital via A E. Yeah, so not for accidents, not for like road accidents, but for all of the other reasons. And they looked at before the Ulez and the year afterwards to Covid come along. Looking at the central London zone, they found that after Ulez came along, so beforehand there was an upward trend in the number of people being admitted to hospital for all of these things through A and E, they found that this trend reduced overall by about 3% once Ulez was in place. And for respiratory disease and cardiac disease, there was changes somewhere around about 8 or 9%, which is pretty dramatic. It takes something that's an upward trend to bringing it to being flat or maybe even a hint of actually going down. And the effect seems to be getting greater the longer time Ulez was in there. But you mentioned the counterfactual and that's really, really important. So with when we're assessing the Ulez, one of the things I was very keen as a reviewer and I had input, I didn't do the assessments, I was an external on them, was that we had a counterfactual so what would have happened if you les weren't in place? And so all the figures from TFL are done with that counterfactual removed. So what would happen with natural fleet turnover for the health studies? So for central London, they looked at what happened and that stands on its own without a counterfactual. This before and after change stands on its own. And that's as I've described. They then did two counterfactual. So they looked at the population in outer London that was less affected by the central London us, and they tried really hard to find another population in the uk, but there's not much that's like central London in terms of the people that live there. There's not so many children in central London, there's not so many old people and there's tremendous ethnic diversity in central London. You don't find other places. They did found Bristol was a close comparator, so they also put that in there. And then they reran their analysis and they found that these changes were still robust with the counterfactual, with one caveat, that the change in respiratory people being admitted to hospital for respiratory needs kind of didn't quite meet the uncertainty thresholds, but the effect was almost certainly still there. The reason for that is that a lot of children get sent to hospital for, you know, admitted through AE with asthma, and we don't see that so much in central London because there's not many children there. So that's really good. So we're talking 7, 8% reduction in people being admitted to hospital for cardiac and respiratory reasons in central London. Then comes along the Bradford scheme. So we don't talk about Ulez is outside Bradford, but Bradford has the second largest scheme in the uk. When that was brought in place, the researchers. There's a fantastic thing called Born in Bradford that follows in great detail all of the hospital records that are generated from GPs and all medical contacts in and around Bradford. And they were able to detect a 25% reduction in. In people going to their GPs for respiratory and cardiac consultations just from the.

[A]

Just as a consequence.

[B]

Well, this is one of the things. Is it a consequence? It follows the introduction of the zone and you can see, if you look at their data, you can see upward trends before and then downward trends afterwards. So they haven't got another Bradford as a. As a counterfactual. So what they tried to do was wait. You know, it's difficult to get, or it has been difficult to get a GP appointment. So how much of that is A factor. So they looked at other types of GP consultation that they didn't think would have anything to do with air pollution. And was there the same pattern in those and that they found that there wasn't.

[A]

That's an astonishing reduction though. I mean, 25% is absolutely astonishing just for a single policy that isn't actually that world changing. I mean, you know, on the scale of all the things you could shift around in life, people driving less in the center of a city and driving polluting cars less in the center of a city is not, you know, it's not the biggest change you could make, but that is a colossal reduction. I'm really surprised and happy that the number is so large.

[B]

Yeah, I think everybody was really surprised that the number was so large. The London figures, of course, are looking just at iron Ear missions. And if you think about this health pyramid, you know, a lot more people get ill and consult their GP and it's only the most ill people that then go to hospital. So the London people are looking at, you know, the much more severe cases and the Bradford people are looking at cases that are less severe.

[A]

So this is very real. I mean, that's the point, isn't it? That the, the, these are, these health impacts are very, very real and apparent. And yet we still have this debate. I mean, it sort of seems to have subsided a little bit in, in London just at the moment, maybe because no particular changes have been proposed in the near future. But, but, but what is the, like, what's your perception of the political. I mean this. Because this is. It always surprised me that the climate change debate, you know, emissions, wasn't more about air pollution because whatever you think of carbon dioxide, you definitely do not want to be bringing, you know, breathing in some black, horrible stuff from the back of a car. Always astonished me that that didn't, wasn't a thing earlier. But what. So like, how, why, why is it that the health argument doesn't win? Right? Why is it that all of us want to be healthy? Nobody wants children to be, you know, getting asthma because of horrible pollution. Why is it that we have an argument about this? Like, why is it so contentious?

[B]

Yeah, yeah. I mean, the evidence that we have on air pollution and health is simply huge these days. You can go onto one of these academic search engines, go onto PubMed and ask about studies on air pollution, air quality, because both are used synonymously and health, and you'll find somewhere in the region of about 70 or 80,000 publications, not all of them will have said it's bad. But there's a very large evidence base. Over 60% of that evidence base has been created in the last century. So, you know, there is a tremendous amount of new things that we know about this that really just haven't been absorbed.

[A]

You mean, you mean this century and the 21st century?

[B]

Yeah, yeah, sorry, yeah, yeah, yeah. So we're, as I said before, we're very much trying to manage the problem that we have in the 21st century using what we knew in the 20th century and not the new knowledge that we've accumulated. So it's a real problem. We're very much lagging behind the science and within the uk, now that we've left the eu, we're lagging behind the best environmental standards that are out there as well. You know, the EU has reviewed all of its evidence, tried to reflect what we've learned in the last couple of decades and changed its limits. It's changed the way it's managing air pollution. And in the uk, we haven't done that, but it's.

[A]

But there's potential. I mean, I'm sort of encouraged by the fact that I'm always encouraged, you know, science having the science is always the first step. Right. And then obviously you have to actually use it, but. And the science doesn't tell a. I mean, it tells a slightly depressing picture, I guess, but in principle that gives you steps you can take to improve things and things have got better. I guess that's the big point about the Eulars, is that now, hopefully no one is going to take it away, partly because those standards will just become normal. The future is cleaner anyway. So let's get to the future more quickly.

[B]

Some politicians are campaigning for its removal.

[A]

Well, let's present them with the evidence. We have not got time to get into the full cult.

[B]

No, no, I'm not going there. But it's just a statement of fact that some people are trying to campaign for its removal. I think we need to change the narrative. Air pollution is normally viewed as a problem that is really difficult to solve. It's also invisible, going back to what you said at the start, so people don't always see it around them. We're normalizing a certain level of illness, we're normalizing a certain level of asthma, we're normalizing a certain level of lung cancer, heart disease, and some of that is coming from air pollution. But we just don't see it because, you know, people get ill for many, many reasons. But we need to change the narrative. We have a lot being talked about, by government, about prevention in terms of health. You know, we've got an aging population. It's going to be increasingly difficult for our, for the NHS as an ill, if it just operates as an ill health service, whereas if it operates as something that becomes preventative, then it can do a lot more societal good. So there is an opportunity here for politicians to come along and actually say, yes, I can make my mark, yes, I can make my legacy. Lots of them worry about their legacy a great deal by doing something for public health. And it's there. And we have evidence from quite a few studies where if you take the air pollution away, for whatever reason, you know, a factory closes or deliberate policy comes along, then the health of the population improves. There's a brilliant study that's come out from the US and, you know, we're starting to move away from steel production, away from burning lots of coal, into electrical methods, these arc furnaces. So we need a lot less coke. So there was a massive coking plant that was closed in a small city in the US and it was incredibly polluting. If you see the accounts of people living in these places, you know, whether they can have their windows open at night, depending on which direction the wind was blowing, their washing would be covered in dust and their children would be obviously getting variable amounts of asthma when they closed the coking works. In the three months that followed, admissions to their A and E or sort of emergency room for heart problems reduced by around 40%. And it's just dramatic if you think you could come up with a drug or, you know, pharmaceutical intervention. That said, you know, I could be reducing GP consultations in the Bradford case by a quarter. In the London case, I could be reducing heart and lung admissions to A and E by somewhere in the region of about 7, 8, 9%. Then, you know, the services that pay for medicine and the medical community would bite your hand off. But we have this, you know, at our fingertips and it's a big prize for a politician to come along and seize. Convincing them is harder.

[A]

Well, that is a great place to finish. We are out of time. Something for us all to think about there. I really like the analogy with the drug. If a drug could do that, we'd all be scrambling all over ourselves to get it. But it's much easier than that potentially, I guess, if we just think about the world a bit differently. Okay, we are out of time. Gary, thank you so much for joining us on the everything electricity.

[B]

Thanks for having me along.

[A]

Well, that was Dr. Gary Fuller, an air pollution scientist at Imperial College London. And I think I am feeling optimistic after that. I mean, hearing about air pollution is never fun, to be honest, but those health stats at the end, that's just amazing. The fact that you can, you know, a single policy can make that much of a difference to every, you know, lots of people's health, not just some subset of the population, but basically everyone who lives in the city, the fact that that's even possible is just amazing. And it's really great to hear about the effort that is going into monitoring air pollution. You know, I'm glad someone's keeping, keeping an eye on all of this. So that is it for this week. That's all we've got time for. And if you have been, thank you for listening.