Exposure to higher levels of air pollution could make mental health problems worse for those already living with them, new research suggests
It can be easy to think of mental health as something that is purely driven by our psychological wellbeing and emotions. But there is a sizeable amount of evidence now that implicates various physical aspects of our lives that can affect it too.
One of those aspects is pollution. The World Health Organization (WHO) recommends a limit of 10 micrograms per cubic metre of so-called 'small particulate matter' (SPM) in order to restrict health complications as much as possible, including mental health issues.
In a study by researchers from King’s College London, the University of Bristol and Imperial College London, the link between air pollution and mental health was explored further, specifically looking at how pollution can affect the severity of disorders in people who already live with them.
The team analysed the electronic mental health records of 13,887 people aged 15 and over who made contact with South London and Maudsley NHS Foundation Trust services between 2008 and 2012.
For each record, a quarterly average concentration of air pollutants – including nitrogen dioxide, nitrogen oxides and fine and coarse particulate matter – were assigned, based on the person's home address. Other factors that could influence the link between pollution and mental health, such as population density and time of the year, were accounted for.
When doing so, a pattern emerged: those who were exposed to higher levels of air pollution went on to use mental health services more frequently, compared with those exposed to lower levels of pollution.
SPM and nitrogen dioxide had a more potent effect than other pollutants, increasing the use of community-based mental health support by 7% and 32%, respectively, over 12 months. In addition, for every 15 microgram per cubic meter increase in nitrogen dioxide, and for every 3 unit microgram per cubic meter increase in SPM, the likelihood of an inpatient stay increased 11% and 18%, respectively.
“There is already evidence linking air pollution to the incidence of mental disorders, but our novel findings suggest that air pollution could also play a role in the severity of mental disorders for people with pre-existing mental health conditions," says Dr Ioannis Bakolis, lead author of the study.
“Our research indicates that air pollution is a major risk factor for increased severity of mental disorders."
A problem that can be addressed
Although air pollutants are an issue for every country, particularly within built-up areas, they are an "easily modifiable" risk factor for increased mental health issue severity, says Bakolis, that can be addressed through public health initiatives like low emission zones.
According to the team's findings, reducing urban exposure to SPM across the UK to those recommended by the WHO could reduce mental health service usage by around 2%.
The team are now looking to investigate the link between air pollutants and a broader range of mental health issues with a particular focus on their effects on children.
Read the full study paper here.
Written by Marco Ricci
Editor and contributor for Talking Mental Health