Health Benefits If Cities Are Densified In Right Way

In short, the solution is to focus on the well-being of residents and not just follow existing standard solutions. This makes it possible to build more homes on existing land while reducing traffic noise, stress and the risk of heart disease.

However, urban planning often focuses on immediate needs rather than long-term ecological values. There is a tendency for construction companies and municipalities to prioritise housing and infrastructure that generate revenue over green spaces, as urban areas are limited and land is expensive. This leads to many parks and recreational areas being sacrificed for development, and clean air, biodiversity and water regulation are often lost permanently.

In an interdisciplinary research project at Lund University in Sweden, researchers have used data and mathematical models to understand and predict the environment and its changes during expansion in the three Swedish cities: Malmö, Lund and Helsingborg. The researchers believe that the difficulties become very clear in the municipalities' plans for denser urban development. While more housing is to be created, the municipalities want to preserve green spaces but lack strategies for balancing dense construction with natural values.

"This lack of clear prioritisation between densification and green values means that the plans risk becoming more of a "fluffy" wish list than a realistic framework for sustainable urban development", says Ebba Malmqvist, researcher at Occupational and Environmental Medicine, Lund University.

More new homes - but not at the expense of residents' health

In Lund Municipality's comprehensive plan, for example, nature and green values are often highlighted as important goals, while at the same time the city is to be densified. Researchers believe this is an example of 'cautious green rhetoric' - the plan emphasises environmental and natural values, but contains few concrete measures for how they will be protected when new homes are built.

The areas of Lorensborg in Malmö and Drottningshög in Helsingborg are both part of the "Million Programme," a large-scale Swedish public housing initiative that delivered one million homes between 1965 and 1974. Large parts of these residential areas already exceed the WHO's recommended noise levels. The next step in the densification of these neighbourhoods is to preserve as much greenery as possible and instead build houses on existing car parks. However, when the researchers calculated the municipalities' expansion plans, the proposal in Malmö meant that the homes would be closer to a major road, which in turn meant that residents would be more exposed to noise and environmental pollution.

In Helsingborg, the plan is to build new housing for senior citizens, where cars will be able to park close to the property. According to the researchers' calculations, this would increase air pollution in an area that previously had little traffic.

"We therefore wanted to investigate how to reconcile the conflict between densifying the city and preserving ecological values by hiring an architect to draw up alternatives to the municipalities' plans. The number of new homes would be the same, but without increasing the impact on health", says Anna Oudin, researcher at Occupational and Environmental Medicine, Lund University.

By building upwards and placing the houses further away from the roads, as well as converting some streets into footpaths and cycle paths, the new proposal would provide the same number of homes but with significantly lower noise levels. The most important measure is to reduce car traffic in order to increase density without increasing the health burden. Prolonged exposure to high noise levels can increase stress levels and impair sleep, which in turn can contribute to an increased risk of cardiovascular disease, including ischaemic heart disease. Through the researchers' modelling to predict environmental changes, they saw that the new proposal would mean a 50% reduction in the number of people with sleep difficulties and a 35% reduction in the number of deaths linked to ischaemic heart disease.

"We need to build vertically and use roofs and courtyards for greenery and maintain green spaces. At the same time, we need to reduce car dependency and prioritise public transport, cycle paths and footpaths. If cities are to be densified without increasing environmental and health costs, car traffic must simply be reduced", Anna Oudin continues.

By planning densification with a focus on health, instead of just following standard solutions, it is possible to significantly reduce the negative effects of densification, according to the researchers. Local authorities need to be more ambitious and include health perspectives to create sustainable and healthy residential areas. With the right planning, noise, stress and heart disease can be reduced as the city grows.

"We often focus only on the city's problems, but here we were able to give municipalities clear information about what leads to greater health problems - and show that something can be done about it. The city of the future will be built through smart planning, where car traffic is reduced in favour of public transport and green spaces become the heart of the city," concludes Ebba Malmqvist.

Breathing fresh air and hearing birds sing in a dense city - how do we get there?

The research project is funded by Formas and has been running from 2019 to 2025. The aim is to look at the conflict between densification and a healthy city, and to create evidence-based support for planning densely populated areas with low environmental impact on health. Researchers from several universities collaborated and shared expertise in modelling environmental impact, mapping green environments and social science analysis. The project also involves three local municipalities in southern Sweden.