Each passing week there seems to be a strengthening in the evidence that air pollution harms our health. Now research in Rome has revealed the impact of air pollution on our mental health. Dr Federica Nobile of the department of epidemiology of the Lazio regional health service explained what led to the research. “Recent studies have linked air pollution to the development of psychiatric disorders, including depression, anxiety, and psychotic episodes. However, all these associations have been mainly investigated in small groups, making their results challenging to generalise.” Nobile’s team started with census data on more than 1.7 million adults that were living in Rome in 2011 and matched these with medical and public health insurance records. Health records were scanned for the next eight years for new cases of mental health problems, including people admitted to hospital or those with new repeat prescriptions for antipsychotics, antidepressants and mood stabilisers. These were compared with air pollution data and traffic noise where people lived as well other societal factors that may affect mental health including poverty, unemployment, education and marital status. They found that people living in areas with higher particle pollution had a greater chance of developing schizophrenia, depression and anxiety disorders. This was matched by analysis of drug prescriptions, where people aged between 30 and 64 had the clearest association with air pollution. Using data from the study, it is possible to predict the benefits from improving the city’s air. Reducing Rome’s average particle pollution by 10% could reduce these common mental health conditions by 10-30%. Even greater improvements would be achieved by meeting the European Commission’s proposed air pollution limits for 2030 and the World Health Organization guidelines. Prof Francesco Forastiere of Italy’s National Research Council and Imperial College London said: “Our discovery underscores the critical importance of implementing stringent measures to reduce human exposure to air pollutants. These are crucial not only for safeguarding against physical ailments but also for preserving mental wellbeing.” Understanding of these issues has been slowly improving. Seventy-one years ago, London’s great smog of 1952 led to the deaths of about 12,000 people, mainly from breathing problems, heart attacks and strokes. Research from the 1990s added lung cancer to the list of air pollution impacts but the effects on brain health were overlooked. A study on pet dogs in Mexico in 2002 helped lead to conclusions that air pollution exposure added to dementia risk in later life. And it was observations of the association between living in an urban area and the greater risk of schizophrenia and other psychotic disorders that led researchers to investigate air pollution as a possible cause. Other studies, including a seven-year investigation led by King’s College London, found that air pollution also had a role in severity and relapse in people with psychiatric disorders such as schizophrenia and depression. Dr Ioannis Bakolis, of King’s College London, who was not involved in the Rome study, said: “The large-scale study in Rome provides much-needed evidence and increases our confidence on the link between air pollution and psychiatric disorders, augmenting previous findings from the UK, US and Denmark. “Rome residents’ average exposure to annual PM2.5 is more than three time higher than what the WHO suggests. Reducing air pollution to WHO guidelines could not only improve brain health but also reduce demand to already overstretched post-pandemic psychiatric services.”