Promoting a healthy cities agenda through indicators: development of a global urban environment and health index

Figures & data

Figure 1. Summary of the development of the BRE Healthy Cities Index 2012 – 2018 (note numbers in brackets are referred to in the main text to orient the reader).

Table 1. Ten key principles to guide development of the BRE Healthy Cities Index.

Principle	Description
1. Clear conceptual framework	Developed from an evidence-based framework of how the urban environment impacts health and wellbeing.
2. Global and local	The global index raises awareness while the indicators can be used locally to develop an integrated approach across city stakeholders.
3. Evidence-based	Each indicator has a clear link to peer-reviewed scientific evidence about the health and wellbeing impact of the urban environment.
4. Focus on avoiding inequalities	Social, spatial and health inequalities are recognised in the index framework and indicators – creating a route for local discussion and action.
5. Aligned with existing data/indicator systems	The index uses open data^5 from existing sources and replicates indicators which have been effective for policy and decision-makers.
6. Peer reviewed	The methodology and evidence base have been reviewed and informed by independent experts.
7. Informed by users	The index and indicators are piloted with built environment and city professionals in their development.
8. Promotes a systems approach	The index framework and methodology takes into account the complexity of urban health factors and promotes a systems approach to evaluating a city’s performance.
9. Spatial	The indicators allow for data to be mapped spatially to inform urban planning policy and decision-making.
10. Focused on built environment	The indicators are about the urban environment impact on health and wellbeing and provide information about factors which are highly influenced by built environment professionals (including urban planning, transport, housing, regeneration, parks, etc.).

Table 2. Ten categories in the BRE Healthy Cities Index.

1. Air quality	6. Noise pollution
2. Food access	7. Resilience
3. Green infrastructure	8. Safety and security
4. Housing and Buildings	9. Transport
5. Leisure and recreation	10. Utilities and services

Table 3. Excerpt from the Housing & Buildings category evidence base for the BRE Healthy Cities Index (note H2 and HP3 are identifiers for indicators within this category, described more explicitly in Table 4).

Category: E.g. Housing & Buildings
Potential indicators	E.g. H2: Number of new building stock certified with a sustainable building standard (e.g. BREEAM [Building Research Establishment Environmental Assessment Method] and LEED [Leadership in Energy and Environmental Design])
Potential policy indicators	E.g. HP3: Policies in place to require new buildings and refurbishment projects to certify to sustainable building standards
Summary of health impact	E.g. There are three main pathways through which housing can affect health: housing tenure, housing neighbourhood and housing as the environment of exposure (Acevedo‐Garcia et al. 2004).
	…
	Within housing as the environment of exposure there are multiple issues that affect health: excess heat or cold and indoor pollutants or mould which can cause/exacerbate asthma, allergies or respiratory diseases (Braubach et al. 2011); poisoning from lead piping, lead paint or carbon monoxide and other building materials (Gibson et al. 2011, Allen et al. 2015); injuries from accidents (slips, trips and falls) or exposure to disease (from pests) related to design and maintenance (Gibson et al. 2011, Allen et al. 2015); lack of smoke alarms, extinguishers and sprinklers increases the risk of injury from fire (Gibson et al. 2011); design may impact psychosocial outcomes (Gibson et al. 2011) (e.g. in relation to daylight, noise and space); exposure to pollutants in adjacent land uses (Allen et al. 2015); opportunity for physical activity through building design (Allen et al. 2015).
Justification for indicators	E.g. H2 & HP3: ‘Green buildings influence human health at two critically important scales: directly at the individual level through providing optimized indoor environments, and indirectly on a population level through reductions in energy use…’ (Allen et al. 2015, p. 251). [REF 1]. ‘For indoor environmental quality, green buildings had lower levels of VOCs, formaldehyde, allergens, ETS, NO2, and PM’(Allen et al. 2015, p. 256). [REF 1]
Link to built environment	Self-evident in this category.
Link to inequalities	E.g. Deprived communities are more likely to be exposed to poor quality housing (Braubach et al. 2011). Informal settlements are likely to have ‘almost no appropriate control over even the most basic regulations for building form and quality’ (Rydin et al. 2012, p. 2092).
Link to other social, economic or environmental impacts	E.g. BRE has estimated that ‘the full cost to the NHS of all homes with significant HHSRS [Housing Health and Safety Rating System] hazards in England might therefore be estimated at £2.0bn in first year treatment costs’ (Nicol et al. 2015, p. 8). ‘Buildings account for about 38% of total global primary energy use and 25% of energy-related CO2 emissions; of which buildings in cities account for two-thirds’ (Rydin et al. 2012, p. 2091). ‘Investing in the energy efficiency of housing can help stimulate the labour market and economy, as well as creating opportunities for skilling up the construction workforce’ (Marmot Review Team 2011, p. 9).
Impact for specific population groups	E.g. The Marmot Review Team has highlighted the health and wellbeing impacts of cold housing on several population groups including children, adolescents and older people (Marmot Review Team 2011).
References for indicators
	Title	Study type	Applicability
E.g. 1	Allen, J.G., MacNaughton, P., Laurent, J.G.C., Flanigan, S.S., Eitland, E.S., and Spengler, J.D., 2015. Green Buildings and Health. Current Environmental Health Reports, 2 (3), 250–258.	Evidence Review of 17 studies	Studies were primarily USA, but may be more widely applicable
Precedence (other urban health indicator tools applying this measure)	E.g. The OECD Better Life Index (Organisation for Economic Co-operation and Development 2016) measures: Percentage of dwellings without basic facilities Housing expenditure, % Rooms per person, Ratio
Data availability	E.g. BRE data on certified sustainable buildings.
Notes	N/A

Table 4. Categories (10) and indicators (58) in the BRE Healthy Cities Index (note an asterisk denotes indicators for which we have identified data and the obelisk symbol denotes indicators also reported in BS ISO 37120).

Category	Identifier	Indicator
Air quality	A1	Concentration of PM2.5 µg/m3*†
	A2	Concentration of NO2 µg/m3*†
	A3	Concentration of PM10 µg/m3*†
	A4	Percentage of population living within 500m of highway or major road
	A5	% of urban land area covered by trees
Food access	F1	Signee to Milan Urban Food Policy Pact*
	F2	Accessibility: Average walking time to food stores selling fruits and vegetables
	F3	Accessibility: the % of no vehicle households living beyond 0.9 mile radial distance of a supermarket
	F4	Availability (home): Number of food stores selling fruits and vegetables within 500m of domestic properties.
	F5	Availability (work): Number of food stores selling fruits and vegetables within 500m of retail and commercial properties.
	F6	% of residents who respond ‘a large selection of low-fat food is available in my neighbourhood’.
Green infrastructure	G1	Hectares of green area per 100,000 population*†
	G2	Percentage change in number of native species*†
	G3	% of dwellings <300m from green space (min. size 1 hectare)
Housing and buildings	H1	number of homeless people per 100,000 population*†
	H2	Number of new building stock certified with a sustainable building standard (e.g. BREEAM and LEED)*
	H3	Housing affordability*
	H4	Building Quality Control Index*
	H5	% of households living in fuel poverty
	H6	% of refurbished building stock certified with a sustainable building standard (e.g. BREEAM and LEED)
Leisure and recreation	L1	m^2 of public indoor recreation space per capita*†
	L2	m^2 of public outdoor recreation space per capita*†
	L3	Access to leisure and recreation facilities: Facilities within <600m per 100,000
	L4	Pre-school playground equipment and physical structures
	L5	Fitness centres per 100,000 population
	L6	Sports facilities per 100,000 population
Noise pollution	N1	% of population exposed to noise pollution measured at Lden >55dB*†
	N2	% of residents exposed to noise levels higher than 35dB during the night
	N3	% of residents exposed to noise levels higher than 45dB during the day
	N4	% of residents who report noise annoyance
Resilience	R1	Greenhouse gas emissions (tonnes per capita)*†
	R2	Residential electricity use per capita (kWh/year/capita)*†
	R3	Electricity consumption of public building per year (kWh/M^2)*†
	R4	Percentage of energy derived from renewables*†
	R5	% of energy efficient building stock
	R6	Urban heat index
	R7	% of land area with green space
	R8	% of land area with reflexive surfaces
	R9	% of buildings with green roofs
Safety and security	S1	Crimes against property per 100,000 population*†
	S2	% of residents who report presence of environmental cues of crime and vandalism
	S3	% of residential neighbourhoods with adequate street lighting
Transport	T1	% of commuters using a travel mode to work other than a personal vehicle*†
	T2	Kilometres of bicycle paths and lanes per 100,000 population*†
	T3	Kilometres of high capacity public transport system per 100,000 people*†
	T4	Kilometres of light passenger public transport system per 100,000 people*†
	T5	Population density (population per km2)*†
	T6	% of roads with speed limits at 20mph or less
	T7	% of residences within 200m of roads with ≥300 vehicles per hour
	T8	% of roads with sidewalks
	T9	Delay crossing roads: Average pedestrian delay
	T10	Street connectivity: average number of three or more-way intersections per square kilometre
	T11	Land use mix: average number of land use types per neighbourhood
Utilities and services	U1	% of population with potable water supply service*†
	U2	% of population with authorized electricity service*†
	U3	% of population served by wastewater collection*†
	U4	% of population living in slums*†
	U5	% of population with regular solid waste collection*†

Table 5. BRE Healthy Cities Index Housing & Buildings category indicator data (standardised and un-standardised) and final category scores (note -/+ in brackets indicates whether the indicator is positively or negatively correlated with health and wellbeing outcomes).

	Un-standardised indicator data				Standardised indicator data
Cities	H1	H2	H3	H4	H1	H2	H3	H4	HCI Category Score
Amman, Jordan		5	1.13	11		0.15	31.58	40.00
Amsterdam, Netherlands	164.00	114	1.64	10	85.51	3.42	50.75	20.00	39.92
Barcelona, Spain	101.44	51	1.44		91.24	1.53	43.23
Bogota, Colombia	133.46	42	0.34		88.31	1.26	1.88
Boston, USA	1096.76	235	1.98		0.00	7.06	63.53
Buenos Aires, Argentina	30.73	12	0.29	11	97.72	0.36	0.00	40.00	34.52
Dubai, UAE	5.89	114	2.42	13	100.00	3.42	80.08	80.00	65.87
Guadalajara, Mexico	20.02	4		12	98.70	0.12		60.00
Haiphong, Vietnam		0				0.00
Johannesburg, South Africa		3	2.95	10		0.09	100.00	20.00
London, UK	139.92	3330	0.47	9	87.71	100.00	6.77	0.00	48.62
Los Angeles, USA	591.94	334	1.77	13	46.28	10.03	55.64	80.00	47.99
Makati, Philippines	58.21	5			95.20	0.15
Melbourne, Australia	156.88	0	1.73		86.16	0.00	54.14
Mecca, Saudi Arabia		12				0.36
San Diego, USA	260.65	281	2.15		76.65	8.44	69.92
Shanghai, China		282	0.40	9		8.47	4.14	0.00
Taipei, Taiwan	21.68	31		13	98.55	0.93		80.00
Toronto, Canada	187.00	58	1.78	14	83.40	1.74	56.02	100.00	60.29
Zagreb, Croatia	50.63	1	0.98	12	95.90	0.03	25.94	60.00	45.47
Min.	5.89	0	0.29	9
Max.	1096.76	3330	2.95	14
Difference	1090.87	3330	2.66	5
Indicator Key	Data Source
H1: Number of homeless people per 100,000 population (-)	World Council on City Data: WCCD Open City Data Portal
H2: Number of new building stock certified with a sustainable building standard (+)	BRE
H3: Housing affordability (+)	Numbeo.com
H4: Building Quality Control Index (+)	World Bank: Doing Business

Figure 2. BRE Causal Pathways Framework (copyright BRE, reproduced with permission).

Table 1 Seven characteristics of complex systems used in proposed Complexity Rating

Characteristic	Description (in urban health terms)	Source	Example for urban health system
1. Dynamic	Health and wellbeing impacts and/or exposures change over time (possibly in unpredictable ways).	(Sterman 2000)	E.g. Air pollution has long term trends (increasing over time), seasonal trends and extremes (spikes) caused by unusual weather events.
2. Number of elements	There are a high number of variables within the sub-system.	(Glouberman et al. 2006, Luke and Stamatakis 2012)	E.g. The urban transport system includes elements related to land use, density, street connectivity, public transport, public space and many others. These interact to create effects such as a walkable community.
3. Interconnected	There are multiple interactions with other sub-systems.	(Sterman 2000)	E.g. Transport emissions affect health through air pollution whilst contributing to climate change which has additional health impacts (e.g. through extreme weather events).
4. Non-linear structure	There is a non-linear relationship between exposure and health and wellbeing impact. Effects are rarely proportional to causes.	(Sterman 2000)	E.g. The impact of vehicle speed on pedestrian injury/death does not change proportionately as speed increase. A collision at 20mph is significantly less likely to cause death than a collision at 30mph.
5. Feedback	Elements within the sub-system interact recursively (in feedback loops) to change the behaviour of the sub-system.	(Sterman 2000)	E.g. When traffic congestion becomes a problem, city officials usually build more road capacity. However this additional capacity disappears quickly as more drivers are attracted. Increasing road capacity is intended to balance out traffic congestion but it has the opposite effect of reinforcing this problem.
6. Counterintuitive	Health and wellbeing impacts are distant in space and time to exposures.	(Sterman 2000)	E.g. The presence of a large number of fast food outlets in a community may result in increased consumption of high energy foods and over time may contribute to increased levels of obesity in the population.
7. Emergent behaviour	Health and wellbeing effects are greater than the sum of the individual effects within the sub-system.	(Glouberman et al. 2006, Luke and Stamatakis 2012)	E.g. A park or 20mph speed limit are not on their own sufficient to support physically active lifestyles. However, when combined with other elements (such as pavements, mixed land uses, street connectivity, etc.) the effect results in higher levels of physical activity than occurs in places which do not have a sufficient breadth of these elements.

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