Given rapid population growth in coming decades, it is critical we rethink the design of Australian cities and the way Australian populations are housed and mobilised. State and federal governments – from both sides of politics - are now (rightly) championing the idea of the 20 or 30 minute city; with inner city neighbourhoods becoming home to many thousands of residents.

While debate about the pros and cons of intensifying land use continues locally, globally it is generally accepted that compact higher density development must underpin a more sustainable future.

There are many potential benefits: Higher density development has the potential to increase access to local jobs, shops, services and public transport, which in turn has the potential to increase active transport modes and public transport use; reduce vehicle kilometres driven by private motor vehicles; improve air quality; reduce traffic congestion; facilitate more affordable housing close to amenity; and reduce the city’s footprint. Fully realized, higher density mixed use cities have the potential to foster healthier and more sustainable lifestyles.

There’s no question that well-built higher density development has the potential to be beneficial. Yet as the saying goes…‘the road to hell is paved with good intent’; and without appropriate guidance, it is easy to get this wrong.

As cities move from single residential to higher density development, it is timely to take stock, to ensure that the benefits of increased density are indeed fully realized; and potential harms are managed or, at best, avoided completely.

The perspective I bring to this debate is a health perspective. What does published evidence1 tell us about the challenges associated with higher density development living for health and wellbeing of residents, and how can these challenges be addressed?

1. Apartment and higher density development living has the potential to impact the mental health and longevity of residents by exposing them to environmental stressors such as noise (from neighbours and traffic), poor air quality and inadequate ambient light. Mandating simple design and constructions features may help. For example, we could mandate that all apartments have adequate noise insulation, ventilation and ambient lighting to avoid these problems.
2. Locating apartments on heavily trafficked roads and near high volume traffic intersections exposes residents to traffic pollution which is consistently shown to be associated with respiratory and chronic disease patterns. Careful thought therefore needs to be given to the location of higher density development. Where possible, higher density housing could be located away from roads carrying heavy traffic and major intersections. However, given community pushback wishing to preserve established suburbs, locating apartments on major arterials is seen politically expedient with less pushback on less attractive sites. If apartments are to be located on heavily trafficked roads, we need to appropriate building design to protect the health and wellbeing of residents. This might include siting buildings to maximise cross ventilation and avoiding balconies overlooking polluted roads.
3. Higher population densities are generally associated with increased crime and disorder: more people circulating, more opportunistic crime. For more vulnerable residents, this potentially constrains their social and physical activities which can contribute to poorer mental health outcomes, physical inactivity and higher levels of obesity. While not the only solution, crime prevention design features can be incorporated into building and neighbourhood designs thereby creating ‘territorial guardians’ and ensuring more ‘eyes on the street’. This includes limiting the number of people accessing building entrances, landings and semi-private space; creating create transitional zones (public, semi-private through to private) and maximising natural surveillance.
4. Living in higher density housing can potentially increase social isolation in residents by limiting the development of social networks and access to social support. Consideration needs to be given to providing opportunities for ‘selective’ interactions between residents – for example, community gardens, workshops. Opportunities for interactions between families and children also need to be designed for. For example, including some larger apartments suitable to accommodate families; co-locating family housing; and providing well-surveilled age-appropriate play areas for young people.
5. Living on high floor levels of high rise buildings can also increase social isolation and has been shown to produce poor health and social outcomes, particularly in lower socioeconomic groups, children and in (stay at home) women with young children. Creating higher density development with human scale (e.g., limiting to five to seven stories), particularly in less affluent areas without the benefit of city or natural views, may be preferable.
6. Inadequate governance and maintenance of higher density buildings can result in disorder and environmental deterioration which has been shown to be detrimental to mental health outcomes in residents unable to relocate. Adequate governance of higher density housing is therefore critical, with opportunities for input into decisions about building management for all residents (not just owners)
7. The likelihood of higher density housing positively impacting the physical and mental health of residents also depends upon its location, the amenity available and neighbourhood’s quality. It is therefore important to locate higher density housing with easily accessible employment opportunities, schools, shops and services (e.g., libraries), recreational opportunities, health-promoting resources (e.g., fresh fruit and vegetables, cycling infrastructure) and public transport to other activity centres.
8. Finally, higher density housing needs to be located in (low allergen) leafy neighbourhoods with high quality public open space and other recreational opportunities that cater for residents across the life course. In developed areas where retrofitting is not possible to create public open space, cities such as New York have closed streets after school and on weekends and holidays to provide age-appropriate safe play areas and local markets. Similarly, school grounds could be made available for community use including providing safe play spaces for children after school, and local farmers markets on weekends.

From a health perspective, the success or otherwise of compact development policies appears to depend on getting three major factors right concurrently: the building (i.e., its location, construction, design, management and maintenance); taking into account the socioeconomic and cultural make-up of residents and the local area; and finally the quality, amenity and accessibility of the local neighbourhood in which the higher density housing is located.

As we hurtle towards growing populations and a higher density future, we need to keep the key goals we are trying to achieve at the forefront of our minds. Clearly a major goal must be protecting the environment for future generations (e.g., this will involve reducing energy and natural resource needs, improving air quality through increased transit use; protecting farmland and natural resources and preserving green space and air, water, flora and fauna systems). A second key goal must be keeping the city productive and moving and doing so sustainability, in the face of rapid population growth (e.g., reducing vehicle kilometres travelled by private motor vehicle and increasing walking, cycling and public transport use). However, other critical social goals must include creating healthy liveable urban environments that minimise overcrowding, noise, and crime; and ensuring a diversity of affordable housing stock that meets the need of diverse populations including younger people, single-parents, children and elderly residents; low and moderate income households.

Decisions we make about land use, transport and housing will have a lasting impacts on the health, well-being of citizens and the sustainability of the planet for future generations. There is already ample evidence that we can use building, transport and land use planning policy levers to optimise outcomes. It’s critical we don’t leave this to the ‘market’, but that we provide developers with a regulatory framework that creates a level playing field, with the aim of producing health, wellbeing, sustainability and liveability outcomes that we can be proud of.

Professor Billie Giles-Corti is Director of the McCaughey VicHealth Community Wellbeing Unit, University of Melbourne and Lead Investigator of the NHMRC Centre for Research Excellence in Healthy Liveable Communities.

1. Giles-Corti B, Ryan K, Foster S. Increasing density in Australia: Maximising the benefits and minimising the harm. Melbourne: National Heart Foundation of Australia, 2012.