In an era where urban populations continue to swell, understanding the intricate relationship between city design and public health is fundamental. The Barcelona Institute for Global Health (ISGlobal) has emerged as a leading voice in this field with its “ISGlobal Ranking of Cities” and the innovative “Healthy Urban Design Index (HUDI).” This comprehensive tool sheds light on the health impacts of urban exposures like air pollution, noise pollution, and access to green spaces across nearly 1,000 European cities.

The ISGlobal Ranking of Cities is more than just a list; it’s a dynamic project aimed at quantifying the health burdens attributable to urban and transport planning. It evaluates various environmental exposures and their associated mortality, presenting cities from the highest to lowest mortality due to these factors. You can explore the tool directly on the ISGlobal Ranking of Cities website.

At the heart of this initiative is the Healthy Urban Design Index (HUDI). The HUDI is a composite score that meticulously assesses the extent to which the configuration of European cities supports the health and well-being of their inhabitants. It examines 13 key indicators across four domains: urban design, sustainable transport, environmental quality, and green space accessibility. These indicators include factors such as urban compactness, housing density, walking and cycling infrastructure, public transport availability, air pollution levels, capacity to mitigate heat, and accessibility of green spaces. Each city receives a score between 0 and 10 for each indicator, culminating in an overall HUDI score.

To ensure meaningful comparisons, cities are classified based on their population size into five categories: Large metropolitan areas (>1.5 million inhabitants), Metropolitan areas (500,000 – 1.5 million inhabitants), Medium-sized areas (200,000 – 500,000 inhabitants), Small urban areas (50,000 – 200,000 inhabitants), and Small towns (< 50,000 inhabitants).

City Spotlights: A Glimpse into the Rankings

Let’s explore the positions of some prominent European cities:

• Madrid (Spain): As a large metropolitan area, Madrid often performs well in indicators related to urban design and sustainable transport. Notably, Madrid has made strides in reducing nitrogen dioxide levels, meeting European standards. In the HUDI for large metropolitan areas, Madrid leads the pack with a score of 6.04, indicating a relatively strong performance in promoting health through its urban configuration. However, historical data showed that lack of green space was associated with the highest premature mortality in Madrid, followed by heat and NO2 pollution. Madrid also reported 43.8% of its population exposed to harmful noise levels.
• London (UK): London, a vast metropolitan area, faces significant challenges related to urban exposures. While specific detailed mortality rankings for London within the ISGlobal framework are part of ongoing research, existing data suggests that large metropolitan areas like London continue to grapple with air pollution levels exceeding WHO recommendations. London reported 33.8% of its population exposed to harmful noise levels.
• Rome (Italy): Rome, another major capital, also contends with considerable urban burdens. Like other large cities, Rome experiences high levels of noise pollution, with 60.5% of its population exposed to harmful noise levels. Studies have also highlighted the impact of urban heat islands on mortality in cities like Rome, emphasizing the need for increased tree cover.
• Berlin (Germany): Berlin exhibits a mixed picture. While it has a lower percentage of its population exposed to harmful noise levels compared to some other capitals (29.8%), large urban centers like Berlin are still working to improve overall environmental quality for their residents.
• Athens (Greece): Athens is unfortunately among the capital cities with higher mortality rates attributable to a lack of green space. This highlights a crucial area for improvement in urban planning to enhance public health. In the metropolitan areas category for HUDI, Athens, as a metropolitan area, sits in the top 3 with a score of 5.86, indicating a decent overall performance despite challenges in specific areas like green space.

A Note on Data Fidelity: Air Pollution

The ISGlobal Ranking of Cities project relies on robust methodologies to estimate health impacts. For air pollution, the ranking focuses on mortality due to fine particulate matter (PM2.5) and nitrogen dioxide (NO2). The calculations utilize an algorithm that considers mortality rates, preventable mortality percentages, and years of life lost due to each pollutant. The project initially published its air pollution ranking in January 2021, using the WHO Global Air Quality Guidelines from 2005 as a benchmark, and subsequently updated the website to incorporate the newer WHO guidelines from September 2021.

It’s important to acknowledge that accurately quantifying air pollution exposure across an entire city is a complex undertaking. The methodology involves a comparative risk assessment approach, comparing current environmental exposure levels to theoretical scenarios where WHO recommendations are met. While ISGlobal employs recent and robust scientific evidence on the relationship between environmental exposures and mortality, the fidelity of the underlying air pollution data itself is a critical consideration. The project openly states that to further improve results, more precise city-specific data on environmental exposures and socioeconomic status would be beneficial, indicating an ongoing commitment to refining their data sources and analyses.

In conclusion, the ISGlobal Ranking of Cities and its Healthy Urban Design Index provide invaluable insights into the health implications of urban environments across Europe. By highlighting the burdens of air pollution, noise, and insufficient green spaces, and by scoring cities based on their health-supportive design, ISGlobal offers a powerful tool for policymakers, urban planners, and residents alike to advocate for and implement healthier, more sustainable urban futures.