 I'm an architect and urban designer by background and I first became interested in density back in the mid 1990s when the compact city was being promoted, certainly in the UK but also in Europe, in the US and in Australia even. And at that time it was being promoted mostly for environmental sustainability reasons to reduce the need to travel by car mainly. And since then our idea of sustainability has shifted from a focus on environment to an integration of social, economic and environmental concerns. And what became, I became very aware at this time that in all of the research on the compact city it tended to be the social aspects that were neglected in the research. And at the same time there was a renewed interest in health in the built environment and I saw a shift from a focus on treatment of illness in hospitals to a focus on promotion of positive good health within homes and communities. So my interest then became in the relationship between the built environment and health and wellbeing. And the main point I'm going to make today is that after 15 years of research in this area, and this is the point I want you to remember I think, is that my view is not the density per se that matters but it's the form in which that density is delivered. So high densities might be okay but it depends how you deliver them. So with that in mind it begs the question what aspects of design do matter and do make a difference to health and wellbeing. And that's the research that I've been doing over the last five to ten years. So I'm just going to present to you some of the different aspects of design that I think are important and are emerging from the research as important. And I can't be comprehensive in ten minutes so I'm just going to give you a few little examples of what might be important. So first of all a key aspect of design and this has been mentioned before today is urban form or housing form. And back in the 1970s Leslie Martin and Lionel March at the University of Cambridge were very interested in this and how you could provide different urban forms of the same density. But they were interested in terms of geometry so they showed and demonstrated that actually to get the same density you could either have your high rise towers or because you need a certain amount of space around those towers you could have lower rise blocks, perimeter blocks that created courtyards in the middle and it may be that those perimeter blocks are the ones that are more beneficial for health and wellbeing and certainly in the studies that have been carried out that address urban form it seems that people are better off in housing which has the traditional form in terms of having a front door onto the street rather than an apartment block. I mean obviously the research has been based in the western world where the idea of high density is very different to the idea of high density here. So that needs to be said that actually if you look at the housing on your right that sort of density is nothing like the density here. Nevertheless where we're trying to deliver high densities in the UK we should perhaps try and aim for housing that is in the form of terraces which have a front door onto the street rather than high rise blocks. Also what might be important in terms of design is the mix of uses and when I talk about mix of uses I mean a fine grain mix of uses not just uses zoned within different areas within the city. So you can have the same density but one is completely residential or you can have the same density where you've got shops, retail, commercial facilities all mixed in with the housing and we know from all of the research on promotion of walking and physical activity that the mix of uses makes a difference to that so it's fairly obvious you're more likely to walk if you've got a local shop or a local facility nearby that you can walk to. Another important aspect to design is the street layout. We've done some research on designing neighbourhood environments for people with dementia, a growing issue of concern for health as our population is aging and we've found in this research that the best street layout for people with dementia is a distorted grid. So we say a grid is good because as you can see from the uniform grid pattern on the left you've got more choices in terms of getting from A to B and it's quicker usually to get from A to B compared to the lollipop or cul-de-sac pattern where you often have to walk long distances to get anywhere and older people can't walk longer distances. However we're suggesting a distorted grid because crossroads is where most people with dementia get lost and with the uniform grid you've got lots of crossroads. If you distort that grid subtly you have T-junctions and then if you also have the road slightly winding or curving that helps people with dementia because they get lost on long straight streets. They forget why they've gone out and what they're doing because they're not stimulated but if the view gradually opens up in front of them they tend to remember why they're there and what they're doing so that's why we promote a regular grid. Another important element that we're finding in our research is the transitional space between the private interior of the home and the public street environment. You might call it a buffer zone and we've just completed a study which was investigating the role of what I call residential outdoor space which is essentially garden space, the private space attached to housing, the role of that space in people's wellbeing. What we found in that research was that the strongest predictor of wellbeing in terms of the built environment variables was having a front garden and although when you ask most people what their ideal outdoor space is they would say having a private back garden it was the front gardens which actually were the strongest predictor of people saying there was good community spirit. The reason for that probably in my view is because the front garden actually provides an ideal area where you can interact with neighbours especially if it's a fairly high density area. This front garden needs only to be a metre or two metres deep to make a difference but what it suggests is that people need to have privacy before they want to interact with their neighbours. If you've got streets that are right onto the pavement they feel their privacy is invaded and actually they retreat from the society around them. If they feel that they can have their privacy, it needs of a privacy satisfied then they're more willing to go out and communicate with their neighbours so a private front garden is important. Another key area is the incorporation of greenery within design and most of the research in this area focuses on the incorporation of large green open spaces or parks but actually what we're finding is that it's the greenery in the more immediate residential environment that might make more of a difference so in terms of providing views of greenery from inside and in a high density area you can provide greenery quite inventively and imaginatively through balcony gardens, through roof terraces, through street trees, grass verges on the streets and so on and I really like the photograph on the right here. You might be surprised to know that's central London and you can see how very green it actually is and I know that the density again doesn't compare to Hong Kong but if you walk around central London it feels very urban and yet it's also very green and in our recent study we found that in more recent housing development housing developed in the 21st century although it's getting slightly larger the amount of space attached to housing what's significant is it's getting less green, it's less green than it's ever been in any housing period previously and I think that's something we need to address and we can do that quite effectively through good design there's also the detailed design of buildings in terms of sound insulation between rooms perhaps having a kitchen dining room as opposed to a living dining room means that family members eat together and talk to each other you might have better relationships you need to have housing design so that different activities can take place at the same time without people getting annoyed with each other I did some research a while ago with psychiatrists which showed that we were looking at the relationship between housing characteristics and depression and we found that in apartment blocks if you lived in an apartment block which had a deck access that's access via this outdoor corridor you were more likely to be depressed and that was after controlling for everything else and I think that was a key finding I won't talk about that one, there's the detailed design of streets which is also important so the concluding slides are that high densities are not in themselves necessarily bad for health and wellbeing and other speakers have agreed with that other aspects of design are probably more important but also we found in our research that there may not be a linear relationship between density and health there may be a curvilinear one so we found for example that low densities and high densities are positive and moderate densities are bad so we need to look at perhaps the limits and the type of relationship and of course importantly the context matters and a lot of the research we've done needs to be replicated in other countries because it's going to be different and we need to bear this in mind because we tend to assume that if we make some change to the built environment it's going to make a difference for health across the board but actually there are conflicts so something that may be positive one aspect of health may be negative for another and how do we deal with that? We need to have some sort of consensus about what is most important, what are the priorities and we have touched on that today and also we're not designing for just one set of people when we design an urban environment we're designing for a whole range of different people and again what's good for one group of people is not necessarily good for another group of people and we need to find a way of taking that into account and it might be that we try and match the right people to the right environment so in general what I'm going to conclude with is that when it comes to the built environment it's the quality that matters not the quantity and for me as a designer that's positive it means the designer's role is important and it's my mission to try and advocate or promote a new approach to design of the built environment one that puts health and wellbeing at the centre and uses evidence in doing so and I think that way if we use that approach then we have the chance to create places that truly help us to flourish as individuals Thank you