The team that I work in runs the London Air Quality Network. This is a network of about 100 monitoring stations in London, but also networks outside London, in Sussex, in Essex, in Hampshire and further afield. [Our job is] making sure that all the analysers are operating properly, recording data properly. That is a huge task, to keep all of them running properly, and all the data coming in properly. And then also to quality assure the data when it comes in, to ratify it, to sign it off, to say: ‘Yes. This was the data for this instrument for this monitoring system for last year’. That’s kind of stuff that we do all the time.
On top of that, because we sit in a university alongside other departments, I work in the measurement team, for the monitoring stations. We also have a modelling team who use quite sophisticated models of London to do projections of what’s going to happen. We have our lung biology department, who investigate how pollution interacts with the lung and then the effect on health, and we have a policy department as well who kind of draw all of those pieces together to write kind of higher level reports for government. So the data drives the bigger higher level pieces of work that we do. But [we are also] getting that data in, making sure it’s good, is important, having it all in one place. [That] allows us to do quite sophisticated analysis on it, trends and so forth, which is the kind of deeper research that we do. Quite often, we’re doing work for either local or central government and the mayor as well.
It’s quite a unique set up. Most European countries [have] monitoring networks run by the city or by the municipal government. It’s an [unusual] scenario to have the monitoring network set up by a university, but the advantage of that is that we have Ph.D students, MSc students, ourselves, adding value to the raw data that comes in by doing more sophisticated analysis. The group’s been going for just over 20 years and I’ve been here for 12 years, and it’s a continually fascinating job.
It was data from the monitoring stations in the early 2000s that started to ring some alarm bells about nitrogen dioxide not going down and, in fact, in some locations, going up. When, nitrogen dioxide is emitted nitrogen monoxide is emitted as well, together we call them NOx and the proportion between NO and NO2 was changing, so that we were noticing more directly emitted NO2. As time has gone on, those NO2 levels haven’t fallen, and, in fact, we’ve got NO2 levels in London that are two or three times higher than the UK limit.
In the last three or four years, that has gradually lead to air pollution rising up the public agenda and we now see air quality in the news more than [we did] six years ago. And then, simultaneously, it has also risen up the political agenda as well, to the point where – during the last mayoral race – air quality was one of the top three issues. When the GLA generally do surveys about what interests people and what they’re worried about, air quality is usually one of the top list, [in] the top three.
So, the monitoring stations are our eyes and our ears, they let us see what is happening on the ground. One example is the Birling Gap mist from last weekend. We detected that moving across in the monitoring stations we have in Sussex. You can see on the monitor when it started and how high it jumped up and moved down and, at a monitoring station a bit further down wind, we saw an effect as well. So a lot of the time, I’m a bit biased because I work in the measuring team with the monitors, but they’re the workhorses of the science and they form the base level of the data that all of the researchers then build upon. ..
I think [the Volkswagen scandal] is an example of why it’s crucial to have monitors, real monitors on the ground, sampling real air long-term. Because you can do modelling, but your modelling is always based on assumptions, on what people tell you or what the manufacturers are telling you, and you can do interventions as well but, in order to know whether something has worked, you have to measure it, to determine whether there’s been a genuine effect or not. Or in fact, whether there’s been an unforeseen effect. And I think that’s where the importance of the monitoring stations really come in.
My boss, Dr Gary Fuller, did quite an in-depth and sophisticated analysis of the monitoring stations about six months ago, where he and the folks he worked with looked at the monitoring stations like a population and said: ‘How does this monitoring station differ from the rest of them?’ And what he saw was [that] some monitoring stations are improving faster than others, and a few are worsening. So that on its own is interesting because it’s showing that some roads are improving faster than others. So then the question after that is: what has happened on those roads that has improved things so much? Are there particular policies that have been enacted on those roads which have lead to the greater improvements and conversely, on the roads that are getting worse, what has happened [there]. So it … gives you an idea of where to look for wins or losses, because very often the monitoring stations are used for post-intervention analysis. So you do something to see if it works, but this was looking at it the other way and saying: here’s some evidence that something is working on this road.
My other colleague, Dr Ben Barrett, did a really good project on Putney High Street a couple of years ago – Putney High Street was for a time the highest NO2 monitoring station on the network. There is Putney High Street, there’s Brixton High Road, there’s Walbrook Wharf, there’s Oxford Street, and these monitoring stations vie for the top spot each year. It changes slightly each year but, whichever monitoring stations are the highest inevitably get the most attention, the most political attention, the most intervention attention. So in Putney High Street, because it was the highest, the GLA took action to prioritise lower emission buses going up and down that road, and my colleague Ben Barrett did some analysis using the monitoring station and using automatic number plate recognition cameras to detect what the change in traffic flow was and then relate that to the changes in the monitoring station… found a decrease by about 20 per cent, which is really good. But that was 20 per cent from over three times the legal limit. It kind of shows you how far London has to go, particularly on NO2 compliance.
The modelling team did a range of scenarios for the think tank IPPR, who commissioned them to do a big report on air quality in London and what we need to do to reach compliance. And there were massive things in there like completely banning diesel and totally changing all the taxis to electric. Even under some of those scenarios there were still some roads in central London that were above the limit. One of the challenges that TFL are aware of is the increase in van deliveries from online shopping and deliveries coming into central London, and the big delivery companies are subcontracting to a man in a van and that’s increasing and increasing. They have a target to reduce the number of vans coming into central London but that reduction is against a backdrop of it increasing, so any reduction fairly ambitious. TFL have levers over the bus fleet and the taxi fleet, but they have less leverage over the man in a van. But they’re well aware of that and, in fact, there’s a lot of local authorities in Business Improvement Districts that are looking at delivery consolidation, trying to get businesses in an area to use one supplier, get all of the waste taken to one place, so there’s just one trip instead of many, many, many trips. There’s a lot of work going on at the ground level to improve things. So I’m generally optimistic. The move to electric is happening; you see car manufacturers coming out almost every week now saying that they’ve got electric models coming on. There’s obviously still a question as to whether we have the electricity generating capacity to handle it, and how that electricity is produced and whether we have the infrastructure to handle it. You can charge your car by trailing a cable out of the window if you live on the ground floor, but if you live on the second, third or fourth floor, then how do you charge your car? So I think the direction of travel is clear: we’re moving towards electric cars, which is great, but I think there’s still a lot of questions about exactly how we get there.
It was perhaps ironic that, because I had asthma as a child and because I was interested in air quality and pollution, I’ve ended up living in one of the most polluted cities in the UK. I’m aware of my exposure because I do this for a job, so I try to take back streets and cycle through the park when I can, every day. But I think the real thing that changed my perspective of living here was having my children, because although it’s one thing for me to decide on the balance between the fun of living in London, versus the probably the worse air quality, that’s a choice I can make for myself, but my children don’t have that choice. I’m choosing for them; it’s a really tough one…I always take my son to football on Saturday mornings and there was a day when we had a really severe pollution episode… A lot of people wouldn’t have been aware it was happening. I knew it was happening because I was getting alerts on my phone on the London Air app all the time, and I had a real dilemma of whether to take him, because playing football is running around outside and breathing more. In the end I took him, because he loves it so much and I felt I really would’ve been denying him enjoyment to not take him. But, really, what would be better is if there weren’t those pollution episodes and he could go and play football and we didn’t have to worry about it. So I guess it gives me an extra incentive to continue to work to improve the situation. But certainly Sadiq Khan has really put it as one of his priorities and there’s real hope there.
We did a study where we looked at the lung health of eight-year-olds growing up in Tower Hamlets and in Hackney, over about a six-year period, to see if the Low Emissions Zone had had an effect. The idea being that, each year, that child would have grown up in a theoretically cleaner environment. So their lung health should be better. The Low Emission Zone didn’t really have an effect so we didn’t really see the effect year over year, but what we did see was a relationship between the annual pollution level, where the child lived, and their lung health. On average the kids we tested had between 5 and 8 percent smaller lung capacity than they should have have by that age, which will stay with them for life really. And that was quite eye opening and quite sad, but the thing which gave me great hope for that was that, every time we went into the school we would do a teaching morning with the kids, and they got it. They understood, they knew that things needed to improve and they knew what they needed to do. They were so optimistic and hopeful about how they were going to improve things and what the future was going to be, with climate change as well. Because air quality and climate change are things that they have grown up hearing about and understanding, [they know] something needs to be done about them. It’s a normal thing for them, not some weird theory that’s come along halfway through their life and they’re like, really? So I was really hopeful, and then they go home and speak to their parents and there’s a ripple effect from that. So I was simultaneously saddened but also hopeful about the future.
One of the tests we did in the study was to get kids to cough, which brings up some cells from the lungs. If you put those cells under the microscope, you can see in them diesel particles. You’ve got them in your lungs; I’ve got them in my lungs – we’ve all got them in our lungs. That’s quite arresting and quite kind of saddening as well that already they’ve got diesel particles in their lungs. So when there’s a pollution event and I’m out playing football with my boy, I know that he’s breathing in these particles and they’re going into his lungs. But you know that’s a really tough one: do I keep him indoors? I can’t keep him indoors all the time – he’d go crazy! I just try to go to parks and avoid the road whenever I can.
Well, we often think about air quality in two categories, personal exposure – and everyone’s exposure is unique as you move around in your day and commuters – and the overall ambient levels. And it’s important to drive down ambient levels because that drives down exposure for everyone everywhere, which is really important. But you also have the ability in your own life to reduce your exposure. Walking and cycling, even walking and cycling by roads, generally has got lower exposure than being in vehicles. I did a study recently that found that overground trains were one of the cleanest ways to get around, because your exposure to pollution depends on how quickly you move through it, so the slower you move through it, the more your exposure is. Overground trains are fast, but they’re also separated from the road network, so they’re one of the cleanest ways to get around. There’s been a study that looked at the dis-benefit of slightly higher exposure from cycling versus the cardiovascular benefit of doing exercise and for running as well, and it found that, in London and in most European cities with these two scales, it’s always of a benefit overall to cycle or walk, and the advantage of cycling or walking is that they don’t produce any pollution either. And we’ve done a few studies this year where generally taking a back street, even if it’s just one block back from the main road, your exposure can be half that than if you were on the main road. One of the things I found from the study is that pedestrians and cyclists have more capability to alter their routes, to take advantage of parks and little alleyways and back streets, than people in vehicles do. I think you’re starting to see diesel sales falling already, which is a good thing. Petrol cars are generally a lot cleaner than diesels, electric even more so, obviously. So I think that shift is starting already, which is good to see.
For a long time, air quality and climate change were seen as completely separate. In fact, looking at them separately can get you into trouble, and in fact a lot of the drive towards diesel was from climate change, because diesel emits less CO2 over the same distance than petrol cars, but emits far more nitrogen dioxide and particulates. Most of the actions that you can take to improve air quality are beneficial to climate change as well. There is a concern at the moment about on site burning of waste and biomass burning – that’s a bit of a concern. That’s potentially good for reducing waste, but it could have a knoci-on effect on air quality, so that’s another case where there needs to be joined up thinking about both of them. I went along to a parliamentary event, bringing a group of MPs and industry together, under this umbrella of talking about both these issues of climate change and air pollution together, to make sure there weren’t the same mis-steps that there has been with dealing with diesel and CO2 in the past. It is far more joined now than it used to be.
There are European cities where car ownership is far lower than it is in London. London has a problem in that it is growing so quickly, and building more public transport infrastructure is really expensive. But if you look at the travel in London reports that look at kind of trends of cycling and pedestrians and tube and bus and driving, it’s generally going in the right direction. Car ownership and driving is on the way down, use of the tube and buses is up and walking and cycling is up. But the problem, because London is growing, … is that the tube and the bus system is at capacity essentially so the only place left, without building new infrastructure, is to encourage people to walk and cycle more. Which is great but, if you’re going to encourage walking and cycling, try not to put people next to traffic.
There’s this interesting kind of future of this combination of autonomous vehicles and electric vehicles. It may be in the future that you don’t own a car, you just kind of summon a self-driving electric car when you need it and then it goes off somewhere. So it could be that, these are things that are going to take many, many years, but … you could envision a future where you don’t necessarily walk down the street and both sides of the street are lined with parked cars that no one is using. And London is pretty well served for parks but the mayor did announce, a couple of weeks ago, that he wants to expand the amount of green spaces in London … which is really encouraging. But the other thing I’d love to see is green corridors [as] ways of getting from one bit to another.
Many years ago I … collaborated on a really interesting art project with an artist from Goldsmiths College. She said: ‘I would love the deer in Richmond park to be able to walk up to my house in Hackney through green corridors that connect places in the city together.’ I think that’s a really lovely image of what the future could be…
That’s the great challenge of air pollution communication: most of the time it’s quite invisible. It’s not like the peasouper fogs that we had in the 50s and I’ve really enjoyed over the last seven or eight working with artists, thinking about ways of trying to make it more visible, but it’s a huge challenge.
The analogy that’s often used is like a muddy glass of water. Even if it had a tiny bit in it, you wouldn’t touch it, because it’s very visible, you can see it. And that’s what the City Air app tries to do. It tries to make it more visible, like if you’re standing and you have two potential routes to walk down and you look at them with your eyes, essentially there’s no difference between them. The app tries to make that more visible.