Throughout the year, we continued providing actionable evidence on the health impacts of urban planning and air pollution. We identified the European cities with the highest mortality linked to air pollution (1) and showed that mortality, at least in some cities such as Barcelona, is highest in the most deprived neighbourhoods (2). The COVID-19 pandemic provided a unique opportunity to assess the impact of a rapid improvement in air quality: around 150 premature deaths in major Spanish cities were prevented during the first lockdown, according to our analysis (3).

Mortality is only the tip of the iceberg: preliminary results from the CitieS-Health citizen science project show that stress and cognitive performance worsen on days when air pollution is highest (4). Similarly, we found that greater exposure to nitrogen dioxide was linked to higher levels of Alzheimer’s disease markers in the brain (5). Our studies also show we can make cities healthier. Promoting a global shift to urban cycling by 2050, for example, would prevent hundreds of thousands of premature deaths (6), and increasing the size of and access to green spaces has multiple benefits including better child development (7) and women’s health (8).

1. Khomenko S, Lancet Planetary Health.

2. Iungman T. Environ Res.

3. Achebak H. Environ Pollut.

4. https://www.citieshealthbcn.eu/

5. Alemany S. Environ Int.

6. Egiguren J. Environ Health Perspect.

7. Jarvis I. Lancet Planetary Health.

8. Triebner K. Environ Int.