A study that explored the links between air quality and mental ill health showed that long-term exposure to relatively low levels of air pollution can cause depression and anxiety.
Tracking the incidence of depression and anxiety in nearly 500,000 adults in the UK over 11 years, researchers found that those living in areas with higher pollution were more likely to experience episodes, even when air quality was within official limits.
Writing in the Journal of the American Medical Psychiatric Association, researchers from the universities of Oxford, Peking and Imperial College London said their findings suggest the need for stricter standards or regulations to control air pollution.
The findings come as ministers face criticism for passing new, legally binding air quality guidelines that allow more than twice the levels of fine particulate matter (PM2.5) compared to equivalent targets set by the world. Health organisation.
Peers this week approved legislation to allow a maximum annual concentration of 12 micrograms per cubic meter by 2028. The World Health Organization completed a review of 2005 air quality levels in September 2021, lowering its limit of 2.5 micrograms to five micrograms.
Air pollution has long been implicated in a number of respiratory disorders, but researchers note that a growing body of evidence demonstrates a link to mental health disorders. However, to date, the only studies available on depression risk have been conducted in areas where air pollution concentrations exceed UK air quality limits.
The researchers drew on data from 389,185 participants from the UK Biobank, modeling air pollution, including PM2.5 and PM10, nitrogen dioxide and nitric oxide, in the areas where they lived. They found 13,131 cases of depression and 15,835 cases of anxiety identified in the sample during a follow-up period of about 11 years.
The researchers found that the higher the air pollution, the greater the incidence of depression and anxiety. The exposure-response curves were nonlinear, however, with steeper slopes at low levels and plateauing trends at higher exposures, indicating that long-term exposure to low levels of pollution was just as likely to lead to the diagnosis as exposure to higher levels.
The researchers said they hope policymakers will take their findings into account. “Given that air quality standards in many countries remain well above the latest WHO global air quality guidelines for 2021, more stringent air pollution control standards or regulations should be implemented in future policy-making,” they wrote.
Anna Hansel, a professor of environmental epidemiology at the University of Leicester, who was not involved in the research, said the study was further evidence to support lowering legal limits on air pollution.
“This study provides further evidence of the potential effects of air pollution on the brain,” she said. The Committee on the Medical Effects of Air Pollution in 2022 reported evidence of an association between air pollution and cognitive decline and dementia. The report concluded that the association is likely causal.
However, there are few studies so far on air pollution and mental health. This new well-conducted study finds associations between air pollution and anxiety and depression in the UK, which has less air pollution than many countries around the world.”