By Emily Midouhas, Theodora Kokosi, Marie A. E. Mueller, and Eirini Flouri.

Read the full paper here.

There is plenty of research showing that parts of our built environment, including greenery and air pollution, especially in urban areas, are important for adult mental health. One reason is that exposure to air pollution can elevate inflammation and exposure to greenery can lessen it. Inflammation is the body’s response to stress or injury and is related to a host of poor health outcomes including mental health problems, especially depressive symptoms. However, researchers have not yet explored this relationship between the built environment, inflammation and mental health in human subjects.

We analysed data collected annually on over 6000 adults living in the UK over a 4-year period to see whether the amount of greenspace and air pollution in one’s neighbourhood was related to having, respectively, better or poorer mental health four years later. Then we looked at whether greenspace exposure could lower systemic inflammation thereby improving mental health and whether more air pollution might lead to inflammation and poor mental health. We found that those who lived in greener areas had lower psychological distress but this was not due to inflammation. Moreover, those who lived in areas with more air pollution did not appear to have poorer mental health.

Increasing greenspace provision and access can have benefits for individuals’ mental health. But we need to continue researching the role of inflammation. Measuring people’s exposures and interactions with the built environment also has many challenges and exploration of these questions over longer periods of time and with more precise measures can help us better understand the processes.