Researchers say smarter urban planning could mean better breathing for everyone
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About 11.6% of asthma cases could be prevented if urban environments were healthier.
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The study combined exposure to air pollution, urban density, and lack of green space.
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Based on nearly 350,000 people across 14 cohorts in seven European countries.
Asthma affects millions worldwide, making breathing difficult and everyday life a challenge.
A recent study led by researchers at the Karolinska Institutet shows how city design especially air quality, urban density, and access to green spaces can influence asthma risk.
The bottom line? Around one in ten asthma cases might be avoided simply by improving the environments where we live, work, and play.
Previous studies have typically calculated the risk of one environmental factor at a time, researcher Zhebin You said in a news release.
We have combined several environmental factors and described how they together affect the risk of developing asthma. This provides a better picture of environmental risks, as life in a city usually involves exposure to several environmental risk factors at the same time.
The study
Rather than isolating individual environmental factors, the researchers took a fresh approach: they assessed the combined impact of three key urban features air pollution, outdoor temperatures (partly tied to the heat island effect), and how dense or grey a neighborhood is.
They used satellite images to classify areas as built-up (grey), green, or water zones. By linking each of the nearly 350,000 participants home addresses with environmental data, they could estimate individual exposures.
In total, the data came from 14 cohort groups across seven European countries. This allowed the team to see how real-world urban living conditions relate to asthma risk.
Results: What they found
Out of the 350,000 people studied, close to 7,500 developed asthma either in childhood or adulthood. The combined exposure to poor air quality, limited greenery, and dense urban layout was linked to about 11.6% of these asthma cases. In other words, in an ideal urban environment, roughly one in ten individuals with asthma might never have developed it.
The researchers emphasized that it's this combination of factors as they occur together in a city that most strongly predicted risk. They suggest that urban planners and policymakers could apply these insights to not only identify high-risk neighborhoods but also design healthier cities in the future.
Looking ahead, the team plans to analyze blood samples from some participants to map their metabolome that is, their body's chemical profile to better understand how environmental exposures influence internal biological processes linked to asthma development.
This is useful for politicians and others involved in urban planning. The method makes it possible to identify risk areas in existing urban areas, but it can also be used when planning future urban environments, researcher Erik Meln said in the news release.
Posted: 2025-08-06 14:52:36