Do green spaces in cities improve the well-being of city dwellers in their everyday lives?
A team of researchers from the Karlsruhe Institute of Technology (KIT), the Central Institute of Mental Health Mannheim (ZI) and the University of Heidelberg investigated this in an interdisciplinary study.
In the first step, a small group of city dwellers evaluated their mood on their smartphones nine times a day. The participants of the first group were between 18 and 28 years old. Later, the researchers used high-resolution aerial photographs to evaluate the proportion of green areas in the vicinity at the time the vote was cast.
In a second control step, 52 other young adults were asked to regularly evaluate their mood in everyday life. After the seven-day survey phase, the volunteers were subjected to functional magnetic resonance imaging (fMRI). This enables certain brain functions to be visualised. The results of the control group were in agreement with the results of the first run.
Sensors record data
Researchers from KIT's Mental mHealth Lab were responsible for recording and evaluating the test persons' whereabouts. They also recorded the well-being on the smartphones in so-called GPS-controlled electronic diaries. In addition, they recorded further sensor data on the physical activity of the test persons in everyday life as well as weather data. They then evaluated the data using multi-level statistical models. This enabled the researchers to determine whether the mood changed when the test persons were in green areas.
Green areas create a good mood
The result: the higher the current proportion of green space in the vicinity of the city's inhabitants, the greater their sense of well-being. The researchers observed reduced activity in the prefrontal cortex of people who reacted particularly positively to green spaces in their everyday lives. This brain region performs a central control function when processing negative emotions and stressful environmental experiences.
For city planners, the results are also interesting from the point of view of health promotion. Accordingly, many urban green spaces could prevent mental illnesses. This finding is important because urbanisation is progressing rapidly. According to the United Nations, more people already live in cities than in rural areas. It is estimated that by 2050 around two-thirds of all people will live in cities.