To calculate the number of avoidable deaths, the study uses city-specific natural-cause mortality data for 2015 from the Eurostat database and applies the most recent and robust scientific evidence on the relationship between exposure to green space and mortality. The study follows a comparative risk assessment approach by comparing current green space levels in cities to a theoretical model in which the WHO recommendation on access to green space would be reached. The number of preventable deaths is estimated as a function of these increases in the availability of green spaces and the scientific evidence on the relationship between exposure to green space and reduction in mortality.