How Urban Design can Impact Mental Health
A great deal of work has been done on how urban design can improve physical health: reducing obesity, or lung diseases, for example. But in the proliferation of research and guidelines for the healthy city, mental health is still often an afterthought. This is disappointing because cities affect our mental health, and mental health problems exert huge impact on cities. This creates a vicious circle.
Urban design holds exciting potential in population mental health. While more research is needed, there is already clear evidence of the ways in which urban design can help promote good mental health, help prevent mental illness, and help support people with mental health problems. This research is ready to be grasped by architects, urban planners, developers, policymakers and others, and integrated into project requirements and project design. It is summarized in our Mind the GAPS framework, which can be applied to any plan or project.
Urban design holds exciting potential in population mental health. While more research is needed, there is already clear evidence of the ways in which urban design can help promote good mental health, help prevent mental illness, and help support people with mental health problems. This research is ready to be grasped by architects, urban planners, developers, policymakers and others, and integrated into project requirements and project design. It is summarized in our Mind the GAPS framework, which can be applied to any plan or project.
Key ways in which urban design can help improve mental health
Green space and access to nature
There are important relationships between accessible green spaces and mental health and wellbeing. Access to natural settings in neighbourhoods and in the course of people’s daily routines is likely to improve and maintain mental health and wellbeing.
Effective for: General mental wellbeing, reduced depression, reduced stress, improved social and cognitive functioning (including for ADHD), and improved mood and reduced aggression for people with dementia.
How it works: There are a range of ways in which green space can improve mental health. The main theories:
- Promotes exercise (see below)
- Provides a setting for social interaction, building social networks (see below)
- Biophilia theory (Edward Wilson): humans have a biological need to be in contact with other species.
- Stress reduction theory (Roger Ulrich): distance from everyday demands, aesthetic appreciation, attention driven by interest.
- Attention restoration theory (Rachel and Stephen Kaplan): facilitates attention without concentration.
Urban design actions points: Green space should be integrated into all designs. While walkable green space seems to have the most impact on mental health, the overall greenness of a person's neighbourhoods is associated with better mental health. The priority is ensuring that people have consistent, regular exposure to urban nature in the course of their daily routines, incorporating features such as street trees and flowers into commutes, views of nature from office windows, and gardens for lunch, in addition to larger walkable spaces where one can exercise and socialize. Of note, to have positive impact on mental health, green space needs to be well-managed to avoid falling into disorder and becoming a place to fear, dislike, or avoid.
Further reading:
Cities, Green Space and Mental Wellbeing by Roe, J. (2016) in: Environmental Science: Oxford Research Encyclopedias.
Greenspace and Health: A Critical Literature Review by Crouche K, Meyers L, Bretherton J (2007)
How to use biophilic urban architecture to promote good mental health by Jonce, Walker, Terrapin Bright Green (2016)
The case for trees in urban design: 5 tools to support better planning by Eva Adler, USAID (2016)
Urban Green Spaces and Mental Health: What does WHO recommend?
There are important relationships between accessible green spaces and mental health and wellbeing. Access to natural settings in neighbourhoods and in the course of people’s daily routines is likely to improve and maintain mental health and wellbeing.
Effective for: General mental wellbeing, reduced depression, reduced stress, improved social and cognitive functioning (including for ADHD), and improved mood and reduced aggression for people with dementia.
How it works: There are a range of ways in which green space can improve mental health. The main theories:
- Promotes exercise (see below)
- Provides a setting for social interaction, building social networks (see below)
- Biophilia theory (Edward Wilson): humans have a biological need to be in contact with other species.
- Stress reduction theory (Roger Ulrich): distance from everyday demands, aesthetic appreciation, attention driven by interest.
- Attention restoration theory (Rachel and Stephen Kaplan): facilitates attention without concentration.
Urban design actions points: Green space should be integrated into all designs. While walkable green space seems to have the most impact on mental health, the overall greenness of a person's neighbourhoods is associated with better mental health. The priority is ensuring that people have consistent, regular exposure to urban nature in the course of their daily routines, incorporating features such as street trees and flowers into commutes, views of nature from office windows, and gardens for lunch, in addition to larger walkable spaces where one can exercise and socialize. Of note, to have positive impact on mental health, green space needs to be well-managed to avoid falling into disorder and becoming a place to fear, dislike, or avoid.
Further reading:
Cities, Green Space and Mental Wellbeing by Roe, J. (2016) in: Environmental Science: Oxford Research Encyclopedias.
Greenspace and Health: A Critical Literature Review by Crouche K, Meyers L, Bretherton J (2007)
How to use biophilic urban architecture to promote good mental health by Jonce, Walker, Terrapin Bright Green (2016)
The case for trees in urban design: 5 tools to support better planning by Eva Adler, USAID (2016)
Urban Green Spaces and Mental Health: What does WHO recommend?
Active space for exercise
Positive, regular activity improves mood, wellbeing and many mental health outcomes.
Effective for: Regular exercise is as effective as anti-depressants for treating mild-moderate depression. Exercise also improves self esteem and wellbeing, anxiety, stress, some symptoms associated with ADHD, dementia, and even schizophrenia (blunted emotions, loss of drive, thinking difficulties). Exercise also helps counteract the weight gain associated with some common anti-psychotic medications, reducing the risk of cardiovascular disease and diabetes.
How it works: The precise mechanisms by which exercise has positive impact on mental health are not fully understood. The main theories:
- Biochemical: Exercise can increase brain chemicals including serotonin (associated with improving mood), and maybe brain-derived neurotrophic factor (increases neurons in the brain).
- Sleep: Exercise improves sleep, which is an important protective factor for mental health.
- Self-esteem: Exercise provides a sense of agency and accomplishment from undertaking a meaningful activity, and can be empowering.
- Stress-resilience: Exercise provides relaxation and stress resilience.
- Social: Exercise provides opportunities for positive social interaction.
Urban design action points: Action opportunities can be embedded into people's routines as they move around the city. One of the biggest opportunities is active transport: increasing safe walkability and bikeability with protected lanes, bicycle parking, and convenient connections between different parts of the city to make walking and cycling more attractive than driving. Alongside this is safety improvements: reduced vehicle speeds, wider sidewalks, longer times to cross roads. Good public transport also encourages walking between train/bus stops and their destinations. Another is the integration of active opportunities into urban places, for example making stairs more attractive than elevators or escalators; installing walking loops in parks, or outdoor gyms. Then of course, dedicated spaces for exercise such as football pitches, tennis courts, running routes, and the like should be prioritised, including access to physical activity facilities for low-income and minority neighborhoods. Mixed-land use is also important: locating residential areas near facilities like schools, shops, and libraries, can encourage walking.
Further reading:
Towards More Physical Activity in Cities (2017) WHO Europe with Gehl Institute
Exercise Interventions for Mental Health: A Quantitative and Qualitative Review by Stathopoulou G, Powers MB, Berry AC, Smits JAJ, Otto MW (2006) in Clinical Psychology: Science and Practice 13:179–193
Exercise and Mental Health: An Exercise and Sports Science Australia Commissioned Review by Morgan AJ, Parker AG, Alvarez M, Jimenez AF, Jorm AF (2013) in JEP online 16(4): 64-73
Environmental barriers to activity: how our surroundings can help or hinder an active lifestyle - Harvard TH Chan School of Public Health
Positive, regular activity improves mood, wellbeing and many mental health outcomes.
Effective for: Regular exercise is as effective as anti-depressants for treating mild-moderate depression. Exercise also improves self esteem and wellbeing, anxiety, stress, some symptoms associated with ADHD, dementia, and even schizophrenia (blunted emotions, loss of drive, thinking difficulties). Exercise also helps counteract the weight gain associated with some common anti-psychotic medications, reducing the risk of cardiovascular disease and diabetes.
How it works: The precise mechanisms by which exercise has positive impact on mental health are not fully understood. The main theories:
- Biochemical: Exercise can increase brain chemicals including serotonin (associated with improving mood), and maybe brain-derived neurotrophic factor (increases neurons in the brain).
- Sleep: Exercise improves sleep, which is an important protective factor for mental health.
- Self-esteem: Exercise provides a sense of agency and accomplishment from undertaking a meaningful activity, and can be empowering.
- Stress-resilience: Exercise provides relaxation and stress resilience.
- Social: Exercise provides opportunities for positive social interaction.
Urban design action points: Action opportunities can be embedded into people's routines as they move around the city. One of the biggest opportunities is active transport: increasing safe walkability and bikeability with protected lanes, bicycle parking, and convenient connections between different parts of the city to make walking and cycling more attractive than driving. Alongside this is safety improvements: reduced vehicle speeds, wider sidewalks, longer times to cross roads. Good public transport also encourages walking between train/bus stops and their destinations. Another is the integration of active opportunities into urban places, for example making stairs more attractive than elevators or escalators; installing walking loops in parks, or outdoor gyms. Then of course, dedicated spaces for exercise such as football pitches, tennis courts, running routes, and the like should be prioritised, including access to physical activity facilities for low-income and minority neighborhoods. Mixed-land use is also important: locating residential areas near facilities like schools, shops, and libraries, can encourage walking.
Further reading:
Towards More Physical Activity in Cities (2017) WHO Europe with Gehl Institute
Exercise Interventions for Mental Health: A Quantitative and Qualitative Review by Stathopoulou G, Powers MB, Berry AC, Smits JAJ, Otto MW (2006) in Clinical Psychology: Science and Practice 13:179–193
Exercise and Mental Health: An Exercise and Sports Science Australia Commissioned Review by Morgan AJ, Parker AG, Alvarez M, Jimenez AF, Jorm AF (2013) in JEP online 16(4): 64-73
Environmental barriers to activity: how our surroundings can help or hinder an active lifestyle - Harvard TH Chan School of Public Health
Pro-social places to encourage positive social interaction
One of the most important opportunities for promoting good mental health is natural, positive social interactions, from close, confiding relationships to feeling part of a community.
How it works: Social interaction builds our self-esteem, self-confidence, and empathy; it increases our feelings of support and belongingness in a community, helps us cope with life's challenges, and mitigates feelings of loneliness, anxiety and isolation. Regular social interactions can also improve cognitive function, particularly memory and intellectual performance.
Urban design action points: Urban places should have places that facilitate positive social interaction (though of course also giving opportunities for privacy). Compact, walkable neighbourhoods provide opportunities for natural, daily social interaction. Mixed-land use can also be helpful, with welcoming shopfronts and nearby amenities, enabling people to browse and interact rather than drive from store to library to office. Fine-grain street fronts can also be helpful: long, monotonous blocks of featureless walls make people prone to ruminations (negative thoughts) and reduce their interest in social interaction.Other opportunities range from street benches and chess tables installed in parks to multi-use public open spaces where people can get together for cooperative community events, ideally with opportunities for participation and volunteering. The research implies that quality is more important than quantity in ensuring good public open spaces. However, in the city people can encounter hundreds of others each day: social interaction must be restricted to avoid overload.
Further reading:
Planning for Wellbeing by Corcoran R, Marshall G. (2016) in Journal of Urban Design and Mental Health 2016;1:5
Quality or quantity? Exploring the relationship between Public Open Space attributes and mental health in Perth, Western Australia by Francis J, Wood LJ, Knuiman M et al. (2012) in Soc Sci Med;74:1570–7
One of the most important opportunities for promoting good mental health is natural, positive social interactions, from close, confiding relationships to feeling part of a community.
How it works: Social interaction builds our self-esteem, self-confidence, and empathy; it increases our feelings of support and belongingness in a community, helps us cope with life's challenges, and mitigates feelings of loneliness, anxiety and isolation. Regular social interactions can also improve cognitive function, particularly memory and intellectual performance.
Urban design action points: Urban places should have places that facilitate positive social interaction (though of course also giving opportunities for privacy). Compact, walkable neighbourhoods provide opportunities for natural, daily social interaction. Mixed-land use can also be helpful, with welcoming shopfronts and nearby amenities, enabling people to browse and interact rather than drive from store to library to office. Fine-grain street fronts can also be helpful: long, monotonous blocks of featureless walls make people prone to ruminations (negative thoughts) and reduce their interest in social interaction.Other opportunities range from street benches and chess tables installed in parks to multi-use public open spaces where people can get together for cooperative community events, ideally with opportunities for participation and volunteering. The research implies that quality is more important than quantity in ensuring good public open spaces. However, in the city people can encounter hundreds of others each day: social interaction must be restricted to avoid overload.
Further reading:
Planning for Wellbeing by Corcoran R, Marshall G. (2016) in Journal of Urban Design and Mental Health 2016;1:5
Quality or quantity? Exploring the relationship between Public Open Space attributes and mental health in Perth, Western Australia by Francis J, Wood LJ, Knuiman M et al. (2012) in Soc Sci Med;74:1570–7
Safety in the city
A sense of safety and security is integral to people’s mental health and wellbeing. Urban dangers include traffic, getting lost, environmental pollutants, and risks posed by other people.
How it works: Feelings of security in daily life is an important contributor to mental health and wellbeing. People who have their property stolen or experience or witness violent crime are more likely to demonstrate poorer mental health for over a year after an incident. Feeling unsafe increases chronic stress and anxiety levels and instills negative feelings about a person's neighbourhood. Furthermore, in places that have higher levels of crime, people are less likely to walk around, or engage in other physical activity and pro-social interactions.
Urban design action points: Crime prevention through environmental design (CPTED) has three principles (and we add a fourth):
A balanced approach is necessary: a safe environment improves accessibility but risk-averse city design can reduce action opportunities and people’s sense of agency and choice.
Further reading
Cities Safer by Design by the World Resources Institute (2015) - guidelines for designing traffic, transit, walkability and biking safety.
Crime Prevention through Environmental Design - Gehl Institute
Crime Prevention through Environmental Design (CPTED) - sample CPTED guidelines from Queensland, Australia
A sense of safety and security is integral to people’s mental health and wellbeing. Urban dangers include traffic, getting lost, environmental pollutants, and risks posed by other people.
How it works: Feelings of security in daily life is an important contributor to mental health and wellbeing. People who have their property stolen or experience or witness violent crime are more likely to demonstrate poorer mental health for over a year after an incident. Feeling unsafe increases chronic stress and anxiety levels and instills negative feelings about a person's neighbourhood. Furthermore, in places that have higher levels of crime, people are less likely to walk around, or engage in other physical activity and pro-social interactions.
Urban design action points: Crime prevention through environmental design (CPTED) has three principles (and we add a fourth):
- Natural access control: Design that makes public routes clear and includes features that discourage access to private spaces, such as placement of entrances, fences and hedges, etc.
- Natural surveillance: Design that increases visibility of the location, so that people feel like they can be seen, and crime victims would be able to call for help, such as ensuring that windows overlook pedestrian areas, increasing pedestrian and cyclist traffic, using appropriately angled lighting to illuminate faces (as opposed to bright light that causes glare and shadows), and avoiding sight-limiting features.
- Territorial reinforcement: Design that clearly demarcate public and private spaces.
- Maintenance: the 'broken windows theory' states that the presence of features such as broken windows gives the impression that the neighbourhood tolerates disorder and lack of oversight, and is unsafe.
A balanced approach is necessary: a safe environment improves accessibility but risk-averse city design can reduce action opportunities and people’s sense of agency and choice.
Further reading
Cities Safer by Design by the World Resources Institute (2015) - guidelines for designing traffic, transit, walkability and biking safety.
Crime Prevention through Environmental Design - Gehl Institute
Crime Prevention through Environmental Design (CPTED) - sample CPTED guidelines from Queensland, Australia
Sleep
Sleep is one of the most important protective factors for good mental health. And yet cities can erode sleep patterns with increased ambient noise and light pollution, and potentially with crowding. Sirens, alarms, vehicle traffic noise, noises from adjacent homes, and construction work may all be more likely in the city. Urban residents are more likely to sleep at times that do not match with their biological clock.
How it works: Noise and light can delay and interrupt sleep. Noise can start to disturb sleep at 40dB, will disturb 15% of sleepers at 65dB and wake a third of sleepers at 60 dB. Even when noise does not cause awakening, it can still disturb natural sleeping patterns by increasing heart rate and causing shifts from deep to lighter sleep and lead to people feeling less rested on waking. Meanwhile, people living in neighborhoods with streetlights and neon lights are more likely to report sleep disturbances.
The relationship between a good night's sleep and good mental health is not fully understood, but research has shown that good sleep fosters better mental health and emotional resilience, whereas poor sleep is associated with negative thinking. People with mental health disorders are more likely to also have sleep disorders, particularly insomnia, For example, people with insomnia are four times more likely to develop depression; conversely, depressed people with insomnia are less likely to respond to treatment, and are at higher risk of relapse. More than half of people with anxiety disorders have sleep problems, and poor sleep can worsen symptoms and prevent recovery.
Urban design action points: Good building insulation, street trees, walls, and other noise barriers can help prevent urban noise from disrupting sleep, as can traffic restrictions. Street lighting can be oriented downwards to reduce residential light pollution, and residential buildings can be designed and rooms oriented to increase darkness in bedrooms.
Further reading
The audible landscape: Physical techniques to reduce noise impacts - US Office of Planning, Environment and Rwalty
Managing the challenge of urban sounds - Earth Journalism Network (2014)
Sleep is one of the most important protective factors for good mental health. And yet cities can erode sleep patterns with increased ambient noise and light pollution, and potentially with crowding. Sirens, alarms, vehicle traffic noise, noises from adjacent homes, and construction work may all be more likely in the city. Urban residents are more likely to sleep at times that do not match with their biological clock.
How it works: Noise and light can delay and interrupt sleep. Noise can start to disturb sleep at 40dB, will disturb 15% of sleepers at 65dB and wake a third of sleepers at 60 dB. Even when noise does not cause awakening, it can still disturb natural sleeping patterns by increasing heart rate and causing shifts from deep to lighter sleep and lead to people feeling less rested on waking. Meanwhile, people living in neighborhoods with streetlights and neon lights are more likely to report sleep disturbances.
The relationship between a good night's sleep and good mental health is not fully understood, but research has shown that good sleep fosters better mental health and emotional resilience, whereas poor sleep is associated with negative thinking. People with mental health disorders are more likely to also have sleep disorders, particularly insomnia, For example, people with insomnia are four times more likely to develop depression; conversely, depressed people with insomnia are less likely to respond to treatment, and are at higher risk of relapse. More than half of people with anxiety disorders have sleep problems, and poor sleep can worsen symptoms and prevent recovery.
Urban design action points: Good building insulation, street trees, walls, and other noise barriers can help prevent urban noise from disrupting sleep, as can traffic restrictions. Street lighting can be oriented downwards to reduce residential light pollution, and residential buildings can be designed and rooms oriented to increase darkness in bedrooms.
Further reading
The audible landscape: Physical techniques to reduce noise impacts - US Office of Planning, Environment and Rwalty
Managing the challenge of urban sounds - Earth Journalism Network (2014)
Transportation and connection
For most people who live in cities, transport use is an integral part of their daily routines.
How it works: Good transport moves people efficiently, affordably around the city, linking communities and increasing people's opportunities for education, employment, housing, leisure, social interaction and access to nature, all of which are important for mental health. Living near public transport connections is associated with better mental health, particularly for older people. Active transport options like bike lanes and walking infrastructure can also improve people's mental health through physical activity, access to nature, safety, and even social interactions. On the other hand, where car infrastructure dominates, roads can split communities, create noise, pollution and danger, and limit active transport options. Time spent commuting is time away from leisure, social activities, and sleep. Stressful commutes are associated with stress, anxiety, aggression and poor sleep. Commuter stress is highest for car drivers, moderate for public transit-users and lowest for walkers and cyclists.
Urban design action points: Specific interventions may include protected bikeways and networks, bikeshares, bus-only routes, and pedestrian plazas to encourage active commuting; and enhancing public transit services.
For most people who live in cities, transport use is an integral part of their daily routines.
How it works: Good transport moves people efficiently, affordably around the city, linking communities and increasing people's opportunities for education, employment, housing, leisure, social interaction and access to nature, all of which are important for mental health. Living near public transport connections is associated with better mental health, particularly for older people. Active transport options like bike lanes and walking infrastructure can also improve people's mental health through physical activity, access to nature, safety, and even social interactions. On the other hand, where car infrastructure dominates, roads can split communities, create noise, pollution and danger, and limit active transport options. Time spent commuting is time away from leisure, social activities, and sleep. Stressful commutes are associated with stress, anxiety, aggression and poor sleep. Commuter stress is highest for car drivers, moderate for public transit-users and lowest for walkers and cyclists.
Urban design action points: Specific interventions may include protected bikeways and networks, bikeshares, bus-only routes, and pedestrian plazas to encourage active commuting; and enhancing public transit services.
Economic stress and affordability in the city
Economic disparities are often particularly marked in cities, with poorer people living in more concentrated neighbourhoods that may be more prone to crime, dilapidation, and poor management.
How it works: People who live in poorer neighbourhoods are likely to have lower self-esteem, feelings of inferiority, and more frustration and hopelessness, particularly when economic disparities are obvious, as is often the case in cities. A wide range of research has also demonstrated the links between dilapidated, deteriorating built environments and urban drug and alcohol use, and crime, leading to feelings of less safety.
Urban design action points: Urban design can seek to reduce the impact of economic disparities. For example, affordable housing that is dignified and well-managed; or affordable transport options including good transport links and active transport options that enable everyone to take advantage of the city's economic, educational, social and cultural opportunities.
Further reading
A systematic review of the relationship between objective measurements of the urban environment and psychological distress by Gong Y, Palmer S, Gallacher J, Marsden T, Fone D (2016) in Environment International.
Economic disparities are often particularly marked in cities, with poorer people living in more concentrated neighbourhoods that may be more prone to crime, dilapidation, and poor management.
How it works: People who live in poorer neighbourhoods are likely to have lower self-esteem, feelings of inferiority, and more frustration and hopelessness, particularly when economic disparities are obvious, as is often the case in cities. A wide range of research has also demonstrated the links between dilapidated, deteriorating built environments and urban drug and alcohol use, and crime, leading to feelings of less safety.
Urban design action points: Urban design can seek to reduce the impact of economic disparities. For example, affordable housing that is dignified and well-managed; or affordable transport options including good transport links and active transport options that enable everyone to take advantage of the city's economic, educational, social and cultural opportunities.
Further reading
A systematic review of the relationship between objective measurements of the urban environment and psychological distress by Gong Y, Palmer S, Gallacher J, Marsden T, Fone D (2016) in Environment International.
Air pollution
For years air pollutants have been implicated in various health outcomes, notably cardiovascular and respiratory diseases. The effects on mental health conditions are less well studied, but there is increasing evidence of the link between air pollution and depression (every 10 μg/m3 increase in exposure to NO2 seems to double the odds of developing depression). There is also evidence of links between air pollution and autistic spectrum disorders in earlier life, and cognitive decline and psychotic disorders in later life. Air pollution is unequally experienced, depending on factors such as city, country, socioeconomic group, ethnic group, and age of people exposed. In the US for example, inner city poorer neighbourhoods experience higher levels of air pollution and associated health impacts, yet in several European cities, central areas are associated with higher housing prices and hence the more well off experience greater exposures, but not necessarily greater health impacts.
How it works: The exact mechanism is not yet understood. For depression, research has found that air pollution is associated with a neuroinflammatory reaction in animal and human models which might contribute to depressive symptoms, but this is not yet proven. The increased risk of vascular dementia is associated with the increased risk of cardiovascular disease. And for psychosis, some reviews of the research have suggested that heavy metals in air pollution may hypothetically produce an epigenetic effect contributing to schizophrenia. (Epigenesis is the process of genes and environment interacting to produce an effect that neither produce on their own.)
Urban design action points: Urban design can reduce people's exposure to air pollutants through: planting trees and green spaces to trap heavy metals and larger particulate matter (e.g. Planus tree species have been used to this effect in London); planning airflow through the urban canopy to help disperse air pollutants from high footfall areas; implementing traffic reduction methods (e.g. low-emission zones, rerouting heavy traffic, and facilitating active transport); and relocating or rezoning heavy industry from densely populated urban areas.
For years air pollutants have been implicated in various health outcomes, notably cardiovascular and respiratory diseases. The effects on mental health conditions are less well studied, but there is increasing evidence of the link between air pollution and depression (every 10 μg/m3 increase in exposure to NO2 seems to double the odds of developing depression). There is also evidence of links between air pollution and autistic spectrum disorders in earlier life, and cognitive decline and psychotic disorders in later life. Air pollution is unequally experienced, depending on factors such as city, country, socioeconomic group, ethnic group, and age of people exposed. In the US for example, inner city poorer neighbourhoods experience higher levels of air pollution and associated health impacts, yet in several European cities, central areas are associated with higher housing prices and hence the more well off experience greater exposures, but not necessarily greater health impacts.
How it works: The exact mechanism is not yet understood. For depression, research has found that air pollution is associated with a neuroinflammatory reaction in animal and human models which might contribute to depressive symptoms, but this is not yet proven. The increased risk of vascular dementia is associated with the increased risk of cardiovascular disease. And for psychosis, some reviews of the research have suggested that heavy metals in air pollution may hypothetically produce an epigenetic effect contributing to schizophrenia. (Epigenesis is the process of genes and environment interacting to produce an effect that neither produce on their own.)
Urban design action points: Urban design can reduce people's exposure to air pollutants through: planting trees and green spaces to trap heavy metals and larger particulate matter (e.g. Planus tree species have been used to this effect in London); planning airflow through the urban canopy to help disperse air pollutants from high footfall areas; implementing traffic reduction methods (e.g. low-emission zones, rerouting heavy traffic, and facilitating active transport); and relocating or rezoning heavy industry from densely populated urban areas.
Mind the GAPS
Our Mind the GAPS framework can be applied to any urban plan or project to help integrate some of the key ideas presented here.
Further reading
Urban Sanity: Understanding Urban Mental Health Impacts and How to Create Saner, Happier Cities. Litman T (2016). Victoria Transport Institute.
A systematic review on the effect of the built and physical environment on mental health. Clark C, Myron R, Stansfeld S, Candy B (2006). Journal of Public Mental Health 6;2:14-27
Understanding the Pursuit of Happiness in Ten Major Cities by KM Leyden, A Goldberg, P Michelbach (2011) in Urban Affairs Review 2011:47;861.
Design for mental health - housing design guidelines by Housing Agency, Ireland