Project title: Green=walkable?: measuring the associations between green space morphology and walking patterns in London among 20,000 respondents in the LTDS.

Project team: Chris Webster (Co-PI), Chinmoy Sarkar (Co-PI), Matthew Pryor (Co-PI), Dorothy Tang (Co-PI), Scott Melbourne (Co-PI), Zhang Xiaohu (Co-I), Ashley Kelly (Co-I).

Project funder: HKU URC-PDF 34th round; FoA dean’s start-up fund; DLA.


Green-space and walking behaviors are intuitively connected. Landscape architects, urban designers and planners tend to use rules of thumb in allocating green space to new and re-fashioned urban spaces, based on inherited wisdom, instinct and a general understanding that ‘proximity to green is good’. This project aims to provide an evidence base for more refined green infrastructure morphologies by quantifying the associations between green morphology and walking. It uses data from London Travel Demand Survey (LTDS) of 2009/10, which administered a one-day travel diary recording route, purpose, timing and mode (broken into discrete stages for 20,000 households systematically sampled from across the city). Green space quantity and morphology was measured from 0.5 metre resolution Blue Sky colour infrared image (NDVI vegetation index), a UKMap spatial database identifying individual street trees, parks and key points of interest (POI) and the Ordnance Survey Integrated Transport Network layer for street networks. Logistical and continuous multi-layer regression models were run to investigate waking behavior (distance walked, routes taken, divergence from shortest path, walk-no-walk) as a function of green space morphology, controlling for PoI, slope, socio-economics, crime, traffic and accessibility.


Specific hypotheses tested include: a positive relationship between street trees and walking; and a positive relationship between park size and walking.


Results so far include the finding that street trees have a measurable effect on distance walked for commuting and on the decision to walk/not walk; and that large parks tend to have a depressing effect on distance walked and the walk/not-walk decision in commuting.


Published so far:

  • Chinmoy Sarkar, Chris Webster, Matthew Pryor, Dorothy Tang, Scott Melbourne, Zhang Xiaohu, Liu Jianzheng. (2015) Exploring associations between urban green, street design and walking: Results from the Greater London boroughs. Landscape and Urban Planning, 143, Nov, 112-125. (IF 3.04)
  • Webster C, Sarkar S, Melbourne S, Pryor M, Tang D, Kaffay N, (2015) Green equals healthy? Towards an evidence base for high density healthy city research. Landscape Architecture Frontiers, 3(1) pp 8-24.
  • Melbourne S, Webster C, Sarkar C, Xiaohu Zhang, Chiaradia A, Does green space size and size distribution matter in optimizing walking performance of cities? Submitted May 2016.
  • Tang D, Webster C, Zhang X, Sarkar C, Does greenery influence walking route choice: a study of 20,000 LTDS participants in London. To be submitted April 2016.
  • Pryor M, Kelly AS, Webster C, Sarkar C,  Quantifying urban greenery. Submitted June 2016.

Anticipated impact:

We hope that this work will set a new standard for the scientific calibration of green-space standards and design doctrines; providing evidence, for example, for decisions about the size-distribution of green spaces in a new city or new neighbourhood and about which parts of a city’s road grid to target in a street tree investment program.

Relationship between access to healthcare and dental services, built environment and dental health within the UK Biobank

Project title: Relationship between access to healthcare and dental services, built environment and dental health within the UK Biobank. 5

HKUrbanLabs research cluster: Healthy CitiesHD

Project team: May Wong (PI), Chris Webster (Co-I), Chinmoy Sarkar (Co-I), Coleman McGrath (Co-I), Edward Lo (Co-I).

Project: UK Biobank application arising out of UKBUMP database.

Abstract: (in preparation for submission as a UK Biobank application)

Anticipated outcomes: 3 publications in high impact journal with the potential for a grant application under URC PDF/RAP scheme co-bided by Dentistry and Architecture.

5Note: This is a HKUrban Lab – DENTISTRY collaboration arising out of core UKBUMP work.

Human – built – natural environment research pillars & synergy. Conceptual urban health niche model of risk clustering and risk pathways - Gene, micro biome, built environment and the corresponding individual health niche (adapted from the Health Niche model of Sarkar, Webster & Gallacher, 2014). Conceptual model developed by Dr C. Sarkar. © Chinmoy Sarkar & Chris Webster

Microbiome – Built Environment project

Project title: Microbiome – Built Environment project. 4

HKUrbanLabs research cluster: Healthy CitiesHD

Project team: Gianni Panagiotou (PI), David Baker (Co-I), Chris Webster (Co-I), Chinmoy Sarkar (Co-I), Seth Denizen (Co-I).

Project funding: Hong Kong University Seed Funding for Basic Research.


Two proof-of-concept pilot studies co-funded by Deans of Architecture and Science. These involve:

  • Relationships between microbiome of Hong Kong’s MTR and underlying urban connectivity. This links to a similar study underway in New York’s Subway and examines ecological patterns of species sampled from MTR hand-rails via indices of ecological dissimilarity and diversity and relates them to underlying urban connectivity.
  • The distribution of anti-biotic resistant pathogens (ABRP) will be assessed via their circulation through bank notes at key locations, especially hospitals within Hong Kong. The hypothesis for the study will be to examine the relationship between ecological distance between the microbiome communities at the chosen sites (as measured by Bray-Curtis dissimilarity index and also Shannon species diversity/heterogeneity index) and underlying geographical connectivity of the sites in urban space.
  • Anticipated outcomes: 2 papers to high impact journals forming the foundation for at least one more major research funding bid.

4Note: This is a HKUrban Lab – SCIENCE collaboration.

Relationship between the built environment and obstructive lung diseases

Project title: Relationship between the built environment and obstructive lung diseases.

HKUrbanLabs research cluster: Healthy CitiesHD

Project Team: Chinmoy Sarkar (PI), Chris Webster (Co-PI), Michael Ni (Co-I), Lydia Liu (Co-I)

Project: UK Biobank Preliminary Application 17796.


This study aims to primarily answer the question: “where does or does not chronic obstructive lung disease (COPD) arise, persist and progress in the UK?”; describing location in detail through measurable attributes of the built environment in which subjects reside. Secondarily, we aim to generate hypotheses to test regarding the relationship between the built environment and respiratory outcomes. Finally, we aim to use historical and prospective data on patients who meet the case definition of COPD and asthma to test our hypotheses about the effect that the built environment has on patients with COPD and asthma.

This study is a collaboration between the University of Hong Kong Faculty of Architecture and School of Public Health. We will take descriptive and analytic approaches, utilizing data from the UK Biobank and the UK Biobank Urban Morphometric Platform (UKBUMP). The UKBUMP is an individual-level built environment database of approximately 750 health-specific built environment metrics for all participants in the UK Biobank prospective cohort.

Anticipated outcomes: A series of 2-3 papers in high impact journals.


3Note: This is a HKUrban Lab – MEDIC collaboration arising out of core UKBUMP work.

Figure. Spatial distribution of some food outlet typologies within Greater London. Map developed by Dr C. Sarkar from UK Map data. ©The GeoInformation Group

Exploring saturation in food outlet access in Greater London, and examining associations with diet quality and body weight in a large sample of adults

Project title: Exploring saturation in food outlet access in Greater London, and examining associations with diet quality and body weight in a large sample of adults. 2

HKUrbanLabs research cluster: Healthy CitiesHD

Project Team: Pablo Monsivais (PI), Thomas Burgoine (Co-I), Chris Webster (Co-PI), Chinmoy Sarkar (Co-I).

Project: UK Biobank MTA 10570; MOU for collaborative research signed by the mentioned team members.


It is hypothesized that the distribution of food outlets in our towns and cities is related to diet and health. However, the scientific evidence base regarding these neighbourhood food environment effects on individuals remains equivocal. It is also unclear whether existing methods of capturing food environment exposure are able to reveal heterogeneity in urban areas considered ‘saturated’. This study will explore potential saturation in food outlet exposure in Greater London, and will examine the extent to which neighbourhood access to food outlets is associated with diet quality, body weight and odds of overweight/obesity in adults. The study will begin by interrogating established built environment measures of food access, already calculated by food outlet type using accurate data from UKMap, for 52,360 adult UK Biobank participants located within Greater London. We will describe exposures to different types of food outlet for the study sample, drawing on precedent from New York City, which has a similarly high population density and potentially saturated food retail environment. Assuming exposure heterogeneity, we will then relate food outlet exposures to frequency of takeaway food consumption, body weight (body mass index and percent body fat) and odds of being overweight and obese.

Anticipated outcomes: A series of 3 papers in high impact journals (one led by HKU).

2Note: This is a HKUrban Lab – CEDAR, Cambridge University collaboration arising out of core UKBUMP work.

“The treatment of a disease represents an admission of failure. Prevention is the goal of medical research and clinical practice.”

Archie Cockrane

Study of the Inverse spatial relationship between slope and urban green in Hong Kong and potential impacts on behaviour and health. a) 30m resolution NDVI index of urban greenness derived from Landsat ETM+ b) 30m resolution urban slope model derived from Aster Global Digital Elevation map. Developed by Dr C. Sarkar. © Chinmoy Sarkar & Chris Webster

Hong Kong FAMILY cohort Urban Morphometric Platform (HKFUMP)

Project title: Hong Kong FAMILY cohort Urban Morphometric Platform (HKFUMP).

HKUrbanLabs research cluster: Healthy CitiesHD

Project Team: Chris Webster (Co-PI), Gabriel Leung (Co-PI), Chinmoy Sarkar (Co-I).

Project Funder: URC 35th Round of PDF/RAP Scheme (HMRF bid for the same proposed by Dr Sarkar had been earlier unsuccessful).


Objective assessment of the built environment (OABE) has evolved into a rapidly developing domain in recent years, enabling automation of detailed and precise measurements of the fundamental determinants of activity behaviour and obesity, physical and mental health in large epidemiological cohorts. The study aims to employ OABE methodology involving a series of spatial and network analyses techniques over multiple spatial databases and remotely sensed data. It will result in the  construction of a series of high resolution objective health- influencing measures of built environment configuration and physical accessibility, modelled from topological models of road, pedestrian and public transport networks; land use mix and housing densities, density/intensity and proximity of health-specific infrastructure; urban green; and terrain. These morphometrics of detailed urban design, density and configuration will be developed at multiple spatial scales and linked to geocoded individual-level household locations of participants of the Hong Kong FAMILY Cohort, the prominent epidemiological cohort of Hong Kong. This will enable the modelling of associations between a suite of urban morphometrics and prevalence of obesity, social capital, mental health and other chronic disease.

Anticipated outcomes: A series of 4-5 papers in high impact journals.


“improved urban health outcomes will need a concerted effort to create and maintain the so-called urban advantage through reshaping city environments. Furthermore, such urban planning needs to take account of the inequalities between cities across the world and within individual cities when devising policy. Urban planning efforts should be based on a complexity approach that recognises multidirectional causality, feedback loops, and unintended consequences. Such an approach is more capable of producing effective action than are more conventional linear approaches. An integral part of such a complexity approach is an emphasis on project-based experimentation and social learning through discursive and inclusive assessment”.

The Lancet Commissions, 2012


Modelling traffic accident causality and built environment in major world cities

Project title: Modelling traffic accident causality and built environment in major world cities.

HKUrbanLabs research cluster: Healthy CitiesHD

Project Team: Chinmoy Sarkar (PI), Chris Webster (Co-I), Sarika Kumari (Research Assistant).

Project Funder: None


The objective is to examine associations between various attributes of built environment density, form, street level physical structures, carrying capacity and various aspects of traffic accident casualty (including frequency and severity). The study includes three major cities of London, Hong Kong and Melbourne.

Anticipated outcomes: A series of four publications in high impact journals. Dr Sarkar will put in a book proposal to Edward Elgar or Routledge in June-August 2016.

Related Publications:

Chinmoy Sarkar, Chris Webster, Sarika Kumari. Does underlying street morphology affect severity of road casualties? A 5-year study of Greater London. Submitted to Annals of AAG, 2016.

Chinmoy Sarkar, Chris Webster, Sarika Kumari. Built environment correlates of traffic accident casualties in children: A five year study of London. Abstract submitted to Environment Planning B (Special Issue), 2016.


“The entire layout of all newly developed areas must, if necessary, be made dependent on that safety factor; it would be rather futile to plan, by means of layout, for hygiene and amenity, but at the same time to overlook that this same layout is likely, daily and hourly, to cause death or maiming”.

Alker Tripp, 1942.

Table. Brief snapshot of built environment morphological metrics of the UK Biobank Urban Morphometric Platform (UKBUMP)

UK Biobank Urban Morphometric Platform (UKBUMP)

UK Biobank Urban Morphometric Platform (UKBUMP): A Big data platform for evidence-based healthy city design

Project Team:

Dr Chinmoy Sarkar1 (Concept Lead, Developer & Principal Investigator), Assistant Professor (GIS, Urban Health & Environment)
Professor Chris Webster1 (Co-Principal Investigator), Dean – Faculty of Architecture & Chair Professor
Professor John Gallacher1,2 (Co-Investigator), Professor & Director – UK Dementias Platform
Ms Sarika Kumari1, Research Assistant

1Healthy High Density Cities Lab, HKUrbanLabs, University of Hong Kong, Hong Kong Special Administrative Region, China.

2Department of Psychiatry, Oxford University, Warneford Hospital, Oxford, UK

Research Centre: Healthy High Density Cities Lab (HealthyHDCities), HKUrbanLabs, University of Hong Kong

Project Funder: The University of Hong Kong Research Assistant Professorship grant, UK Economic & Social Research Council Transformative Research grant, UK Biobank (UKB Research application 11730)

 “Understanding the urban factors that are risk or protective factors for health can capitalize on the positive aspects of urban living and lead to the development of appropriate interventions and preventive measures. Given the growing predominance of the urban living, interventions that take into account features of the urban environment have the potential to be widely applicable and to influence the health of vast number of people”.

Vlahov and Galea, 2003

The Guardian. 6th Oct. 2017. Inner-city living makes for healthier, happier people, study finds

Daily Mail. 6th Oct. 2017. Cities make healthier, happier people.–report.html

International Business Times. 6th Oct. 2017. We’re better off living in cities – and here are three reasons why

Thompson Reuters. 5th October 2017. Cities make for healthier, happier people – report.


The study was conducted using the UK Biobank resource (approved UK Biobank Research application: 11730). The authors thank the Ordnance Survey (UK national mapping agency) for providing access to its UK-wide spatial data for use in this study.