The ISGlobal Ranking of Cities is an ongoing project aimed at estimating the health impacts of urban and transport planning in 1,000 European cities.

This research project evaluates various environmental exposures related to urban and transport planning (such as air pollution, lack of exposure to green spaces, noise from road traffic and heat island effects) for cities in more than 30 European countries and establishes different rankings with the results.

The first phase of the project focuses on air pollution, one of the greatest risk factors for disease and death worldwide.

A study led by researchers from the Barcelona Institute for Global Health (ISGlobal) has for the first time estimated the impacts of air pollution on health in Europe at the city level. Since disease data is not available for all cities, the study focuses on mortality.

The research team estimated the annual mortality due to air pollution for each of the 1,000 cities included in the study and drew up two rankings on the basis of the results: one for fine particulate matter (PM_2.5) and one for nitrogen dioxide (NO₂).

After pooling together cities included within the same metropolitan area, the final ranking includes 858 European cities. The city ranked #1 is the one with the worst mortality data related to air pollution, while the city ranked #858 has the best mortality data.

The air pollution ranking is based on a mortality burden score assigned to each city. Scores were calculated using an algorithm that takes into account mortality rates, the percentage of preventable mortality and the years of life lost due to each air pollutant.

The ranking was published in January 2021, using the WHO Global Air Quality Guidelines from 2005 as one of the target scenarios. Since the WHO published new guidelines in September 2021, the website was then updated to include the new air pollution reference levels as counterfactual scenarios.

The second phase of the project focused on the exposure to green spaces in the cities.

A study led by researchers from the Barcelona Institute for Global Health (ISGlobal) estimated for the first time the impacts of lack of exposure to green spaces on health in Europe at the city level. The study focused on the impacts on mortality.

The research team estimated the annual mortality due to lack of exposure to green spaces for each of the 1,000 cities included in the study and drew up two rankings on the basis of the results: one for the normalized difference vegetation index (NDVI) and one for percentage of green area (%GA).

After pooling together cities included within the same metropolitan area, the final ranking includes 866 European cities. The city ranked #1 is the one with the highest mortality burden attributable to the lack of exposure to green space, while the city ranked #858 has the lowest mortality burden.

The green space ranking is based on a mortality burden score assigned to each city. Scores were calculated using an algorithm that takes into account mortality rates, the percentage of preventable mortality and the years of life lost due to each green space measure considered.

The third phase of the project focused on noise from road traffic, one of the main environmental risks to health and wellbeing.

A study led by researchers from the Barcelona Institute of Global Health (ISGlobal) has for the first time estimated the health impacts of road traffic noise on health for a large number of cities in Europe simultaneously. The study focused on high annoyance caused by this source of noise and mortality from Ischaemic Heart Disease (IHD) causes.

The research team estimated the proportion of population exposed to noise levels harmful for health (over 55 dB Lden), the proportion of population highly annoyed and the annual number of avoidable deaths. In this phase of the study it was not possible to include all 1,000 cities due to lack of data. Estimates are available for 749 cities.

The research team did not establish a ranking for this environmental pollutant because the estimates for European cities were considered not comparable due to issues related to data formats and quality.

Our studies are based on the quantitative health impact assessment methodology. This methodology follows a comparative risk assessment approach by comparing current environmental exposure levels in cities to theoretical scenarios, in which at least the WHO recommendations are reached. The health impacts are estimated as a function of the differences between current and theoretical scenarios, using the most recent and robust scientific evidence on the relationship between environmental exposures and mortality.