 Air pollution affects us throughout every stages of our lives and attacks almost every organ of our body. It kills up to 7 million people every year worldwide. Undeniably, something needs to happen. We need to tackle urgently air pollution. And in the past, much of our solutions have focused on very technological approaches. Better fuels, better efficiency, more emissions controls. And this is far too narrow an approach. Yes, of course, technology has its place, but it's a hugely missed opportunity for much more holistic thinking about improving health of citizens. So I'd like to take the air pollution problem, turn it on its head, and think of it not as a problem, but as an opportunity. So why are an opportunity? Let's step back for a second and think, why is it that we want to tackle and reduce air pollution? Any guesses? It's to improve health, right? So then why not make health the goal of our air quality policies? And if health is the goal of air quality policies, does it really make sense to keep on having the same traffic-loaded streets and just perhaps slightly better from improved air quality around them? Or do we want to rethink the purpose of our streets? Are they really just for cars to go from A to B? Or can they also be for people to be able to walk, bike, talk to their neighbors, children to play? So I think this vision of a human scale, healthy and sustainable city is possible. Much of my research at Imperial College is focused on developing the evidence of how and why we should develop holistic thinking around developing urban strategies that address health in a much more holistic way than just purely technologies. So I've developed some compelling evidence and I'd like to show you a few examples. So for example, in a modeling study that I did in Barcelona in Spain, we were interested in looking at the health impacts of reducing 40% of the car traffic in the inner city. And when we look purely at the air pollution benefits, we found that about 10 deaths could be avoided every year. But then we assumed that these car trips were replaced with walking and cycling trips and then we found 67 deaths could be avoided almost seven times the benefits thanks to additional physical activity. A case study that I'm doing currently in London, we're comparing purely technological solutions to reach air pollution targets to behavioral solutions that integrate walking and cycling. And there we're finding 20 times the benefits from the walking and cycling scenarios compared to the technological solutions thanks to the additional physical activity benefits. But of course, who here hasn't at some point doubted and hesitated in cycling or walking in a city? Much of my research is also about understanding the determinants of travel behavior and clearly fear of traffic, mostly fear of traffic crashes, but increasingly air pollution is one of the biggest hindrances to cycling in cities. And people are right. Some of the monitoring studies that I've done have shown that if you walk or bike as part of your daily lives to go places, you're likely to inhale 50% higher air pollution compared to if you were to drive to go places throughout your day. So on balance, whether the risks and benefits? Well, thankfully, most of our modeling studies have a rather positive message that the benefits outweigh the risks. So in the case of Barcelona that I showed you a second ago, the benefits of physical activity were 60 times higher than increased risk from inhalation of air pollution or traffic injuries. But in some parts of the world, for example, here in China and Beijing, we see that if you cycle more than an hour and a half every day, you start accruing more harm than good because of the high levels of air pollution. Now, the epidemiological analysis that I've taken part of also generally have a rather positive message of benefits outweighing risks. However, if we look specifically at some health outcomes and look at older people, some of the benefits from physical activity start being attenuated or even sometimes canceled out at high levels of air pollution compared to the low levels of air pollution. Clearly, we need a holistic approach to tackling these problems. What we need is a new vision of cities where the space provided to cars is diminished and where we increase the space given to citizens so they can walk, bike, interact, and play. Some cities around the world have starting calling for and making bold announcements about going car-free or carless, such as Hamburg, Madrid, Oslo, or Paris. So we're starting to get there. So, yes, air pollution is clearly a major public health problem that has to be tackled. Let's get a much bigger bang for our buck by having a holistic approach which integrates urban planning decisions rather than purely technological solutions to tackle it. We can all make this happen by working together. So let's start now rather than later so we can start reaping the benefits earlier rather than later. Thank you.