Air Pollution Linked to Higher Suicide Risk in Review, Experts Caution

Their meta-analysis of 29 studies found that exposure to airborne small particulate matter and nitrogen dioxide was linked to a heightened risk of death by suicide, suicide attempts and suicidal ideation. A narrative analysis of 16 further studies suggested that some other air pollutants, including sulphur dioxide and ozone, as well as noise pollution, were also associated with a higher suicide risk. Evidence for light and water pollution was inconclusive.

The authors said the findings suggested environmental pollution could be considered in suicide prevention strategies and that suicide prevention should also be viewed as a public health issue. “These findings bring to attention the critical importance of recognising environmental exposures as modifiable risk factors within suicide prevention efforts,” they said. They added that integrating environmental health into mental health policy through cross-sectoral collaboration, pollution reduction strategies and targeted public health interventions could play a vital role in reducing suicide risk and improving overall population mental wellbeing.

Other experts expressed caution. Dr Jess Moody, senior research and evidence manager at Samaritans, said that while the reasons for suicide are complex, evidence shows a variety of factors can affect suicide risk and that the environments people live in, particularly inequalities around living conditions, should not be ignored. She said Samaritans welcomes research that helps awareness of how suicide links to wider public health concerns.

Dr Jon Van Niekerk, chair of the general adult faculty at the Royal College of Psychiatrists, said the research suggested some forms of air pollution may be associated with a small increase in suicidal behaviour, but it did not establish that air pollution itself caused suicidal thoughts or attempts. He added that air pollution is closely associated with other factors known to influence mental health, including socioeconomic deprivation, urban living, physical health and housing. The study provides further population-level support for reducing harmful air pollution, he said, though the findings should not be seen as supporting individual suicide risk prediction or suggesting that pollution reduction alone could be a suicide prevention measure.

Dr Rosie Cornish, a senior research fellow in epidemiology and health data science at the University of Bristol, said many factors are associated with higher levels of air pollution as well as increased risk of suicide. “If air pollution is not actually a cause of increased risk of suicide then reducing pollution will not help to prevent suicide. The authors do not acknowledge this when drawing their conclusions,” she said. Dr Stephen Burgess, professor of biostatistics at the University of Cambridge, said the study confuses two fundamentally different concepts: causation and association. He said many other factors could potentially explain the observed associations, such as areas with higher pollution differing in other ways that affect suicide risk. Further research is needed to claim that the identified factors are causes of increased risk, he said.

More than 720,000 people globally die by suicide each year, according to the World Health Organization. It is the third leading cause of death among 15- to 29-year-olds.