A large-scale European study discovered that living in crowded places with poor air quality and fewer green spaces increased the chance of acquiring asthma in both children and adults. The study, coordinated by Sweden's Karolinska Institutet, examined data from over 350,000 people in seven European countries. It discovered that more than 11% of asthma cases might be attributed to a toxic combination of city pollution, bad urban design, and a lack of natural places. 

Unlike previous research, which focused on only one issue at a time, this one examined the cumulative impact of various environmental threats. "This gives a better picture of how city living impacts health," noted Zhebin Yu, one of the primary researchers. His team used satellite photographs to determine how much of each community was made up of grey (buildings), green (parks or trees), or blue (water bodies). This was combined with pollution and temperature records to determine each individual's risk exposure. 

The findings were clear: city inhabitants who lived in locations with heavy pollution, densely packed buildings, and no greenery had a significantly increased risk of acquiring asthma. During the study period, over 7,500 patients received a new diagnosis of the illness. 

Asthma is a chronic disease in which the airways become inflamed and narrowed, making breathing difficult. It can be caused by allergies, chilly air, or pollution. Though commonly linked with childhood, it can start at any age. 

This research provides valuable insights for governments and municipal planners. "The method helps identify high-risk areas in current cities and can guide healthier designs for new ones," said Erik Melén, another senior researcher working on the study. 

The researchers will then analyse blood samples from participants to map their metabolome, which is a thorough snapshot of chemical activities that occur in the body. The objective is to discover how contaminants affect human health on a molecular level. 

This study is part of the larger EXPANSE project, which is sponsored by the EU's Horizon 2020 programme and is looking into how a person's exposome — the sum of all environmental exposures over their lifetime — contributes to diseases such as asthma, heart attacks, stroke, and diabetes. 

In a world where more people live in cities than ever before, this study serves as a stark reminder that the way we design our environments has a significant impact on our health, often in subtle but deadly ways.