Exhaust fumes are damaging our lungs, hearts, and now mental health. 


Life in a heavily polluted city has been associated with poor mental health for several years now, but a recent study shows that even low pollution rates may increase the severity of mental illness considerably. 


The study, published in the British Journal of Psychiatry, is the most comprehensive of its kind. It involved 13,000 people in South London and correlated the level of air pollution inside their homes with their contact with mental health services. The findings were unsettling: 


  • A small increase in nitrogen exposure led to a 32% increase in the risk of needing community-based treatment. 
  • A small increase in nitrogen exposure led to an 18% increase in the risk of hospital admittance due to mental illness. 
  • The risk was higher in patients with pre-existing mental health disorders like schizophrenia, bipolar disorder, and depression. 
  • The link between poor air quality and mental health disorders remained seven years after the initial evaluation. 

What’s more, there didn’t seem to be any other explanation other than the low air quality behind the phenomenon. Nitrogen, the main culprit behind poor mental health, is mostly emitted by diesel vehicles, but it can also be caused by burning fossil fuels. 


Even though pollution levels have dropped slightly in recent years, London still one of the cities with the lowest air quality, and reducing pollution levels by just a few units, to the 10µg/m³ limit suggested by the World Health Organisation, could greatly improve the wellness of city dwellers and save the NHS millions of pounds every year. Currently, pollution rates in South London vary between 18-96µg/m³, but, according to Lead researcher Ioannis Bakolis of King’s College London, there are no safe levels of air pollution, because “Even at low levels of air pollution, you can observe this kind of very important effect.


Globally, air pollution costs the world economy over £3.6 trillion every year, and that only includes the best-known physical risks to the heart and lungs. Factoring in mental health risks raises the costs even more. 


The study proved that the link between air pollution and poor mental health is biologically possible and rings the alarm for authorities to cut down on fossil fuels. It’s not the first time that researchers examine the detrimental effects of air pollutions on mental health. In 2019, global research concluded that air pollution could be harming every organ in the human body, including the brain. Thus, long-term exposure to air pollutants can increase the risk of anxiety and depression, suicide, and mental disorders in general. It can also lead to a decline in cognitive intelligence. 


Although the study participants came from South London, researchers point out that the study applies to all cities with heavy diesel vehicle traffic. The study adds to the growing body of evidence suggesting that pollution doesn’t just take a toll on our physical health, but on our mental health as well, and that the issue needs to be tackled as quickly as possible. According to Dr Adrian James, President of the Royal College of Psychiatrists, “The environmental and climate emergency is also a mental health emergency.”