What Policies Could (Compact) Cities Adopt to Reduce Their Health Burden?

Mayors can ease the burden on local GPs and hospitals by adopting effective policies in favour of healthier cities.

We recently evaluated the relation between urban configurations and mortality in more than 900 European cities and found that compact-high density cities had a higher mortality rate than green-low density cities.

Most of the population in the study resided in compact high density (68,096,496 people) and open lowrise medium density (56,108,876 people) cities, compared with the open lowrise low density (38 559 619 people) and green low density (27,474,508 people) city types.

The higher mortality rates in compact cities could be explained to some extent by the higher levels of air pollution, lack of green spaces and higher heat island effects, which is partly due to the much higher density of motorised traffic. Motorized private traffic requires much space that could be used in a better way e.g. for green space that also reduces urban heat island effects. High air pollution levels, due to the density of residential and traffic sources, are a particular challenge for compact cities and a reduction in the levels will reduce the mortality rates and associated disease burden significantly.

Leveraging compact cities

Compact cities have a significant advantage over other types of cities in that they can accommodate many more people in a relatively small area, and thereby reducing damage to natural areas and allowing for active and public transport. It is still the dominant urban configuration in Europe. And the CO₂ emissions per capita are much lower than in other configurations.

We need to exploit the potential of our compact cities through innovative models

We therefore need to exploit the potential of our compact cities through innovative models such as the Barcelona Superblocks, the Paris 15-minute city, the London Low-Traffic Neighbourhood or the Vaugban, Freiburg car-free neighbourhoods, incorporating alternatives such as nature-based solutions, including tree planting and green roofs and facades. It is essential to reduce the use of private cars and to shift even more to active and public transport.

In addition, (ultra) low emission zones (LEZs) can be an effective way to reduce air pollution, as can tolls to reduce the number of private cars entering the city. Of course, there is no one-size-fits-all solution for all cities. Each city should conduct specific studies based on its own characteristics and design an ad hoc solution to find the optimal model in terms of health, environmental quality and carbon footprint.

But by how much can the health burden be reduced? The Barcelona example

In recent years a number of health impact assessment studies have been carried out to estimate the health burden associated with urban and transport planning in Barcelona. Some back-of-the-envelope calculations can give some indication of what might be effective policies in a compact city like Barcelona. Barcelona has a mortality rate similar to the average of the compact cities in the study (1124 deaths per 100,000 people) and much higher than the mortality rate in green low density cities (1003 deaths per 100,000 people). How can these higher mortality rates be reduced and brought closer to or lower than the green low density cities?

1. If air pollution, noise and excess heat were reduced to internationally recommended levels, and increasing green space and physical activity to the levels recommended by the World Health Organisation, would prevent 2,904 deaths per year. This would reduce the mortality rate by 213 deaths per 100,000 population. 
2. If only air pollution levels were reduced to the new WHO recommended levels, an estimated 1886 deaths could be prevented annually (1,307 deaths for PM_2.5 and 827 deaths for NO₂). This would reduce the mortality rate by 139 deaths per 100,000 people, or 42 per 100,000 if only NO₂ would be reduced to recommended levels.
3. If 503 of the original Superblocks were implemented in Barcelona, it is estimated that 667 deaths could be prevented each year through some reduction in air pollution, noise, heat-island effects and an increase in green space and physical activity. This would reduce the mortality rate by 51 deaths per 100,000 people. 
4. If green space were increased to provide everyone citizen with sufficient access to green space according to the WHO (at least 1 hectare within 300 meter of the residence), 337 deaths could be prevented annually. This would reduce the mortality rate by 27 deaths per 100,000 people. 
5. If every street in Barcelona had a cycling lane, cycling rates would increase to an estimated 19% of the transport mode share, physical activity levels would increase and 248 deaths could be prevented each year. This would reduce the mortality rate by 15 deaths per 100,000 people.
6. If 40% of short car trips shifted to cycling would prevent 66 deaths per year, and shifting some to public transport would prevent 44 deaths per year in the adult working population and 10 deaths in the general population. This would reduce the mortality rate by 4 deaths per 100,000 people and 3 deaths per 100,000 people respectively. 

It is clear from these examples that the higher mortality rate in compact cities could be reduced by improving environmental quality, especially but not only air quality and green spaces, and by increasing physical activity levels. Of course, there is no single magic policy measure and it is likely that a mix of different measures will be the most effective and feasible to reduce the health burden.

Who can make the changes?

Public health researchers like us can estimate the health burden and provide examples of how it could be reduced, but we cannot make the changes. In this case, urban planning, mobility, environment, climate and education departments, to name but a few, under the leadership of the local mayor, should propose actions and implement the changes needed to reduce the health burden in their city. In this way too, through decisive and effective leadership, the mayor can reduce the heavy burden on the local health system (e.g. GPs, hospitals, social services) and lead a more sustainable, liveable and healthy city. 

READ THE NEWS ABOUT THE STUDY: Compact cities have lower carbon emissions, but poorer air quality, less green space and higher mortality rates