EXPOSURE to air pollution may increase the risk of suicide and suicidal behaviour, according to a major review of international research.
Researchers found that both short and long-term exposure to common air pollutants were associated with an increased risk of death by suicide, attempted suicide, and suicidal thoughts.
The WHO estimates that currently, 99% of people worldwide live in areas where air pollution levels exceed its guideline levels. These new findings raise concerns that further to its well documented impact on physical health, environmental pollution could be an overlooked factor in mental health and suicide prevention.
Air pollution emerged as the most widely studied environmental exposure, featuring in 38 studies, when researchers from Queen’s University Belfast reviewed 45 studies examining links between environmental pollution and suicide-related outcomes.
When they pooled results from 29 studies, they found significant associations between short-term exposure to fine particulate matter – known as PM2.5 and PM10 – and the risk of death by suicide and suicidal behaviours.
Long-term exposure to PM2.5 and nitrogen dioxide (NO₂), a pollutant commonly produced by road traffic and fossil fuel combustion, was also significantly associated with increased risk.
The review found some evidence linking other pollutants, including sulphur dioxide and ozone, with suicide-related outcomes. Noise pollution may also play a role, although evidence for water and light pollution was inconclusive.
The findings add to growing evidence that the environment people live in could influence mental as well as physical health.
The researchers highlighted several potential explanations for the association. Exposure to air pollutants has previously been linked to chronic inflammation and neurological damage, which could affect brain function, mood, and responses to stress.
It has been shown that noise and light pollution may also disrupt sleep and the body’s circadian rhythm, potentially contributing to poorer mental health.
However, the researchers stressed that the findings do not prove pollution directly causes suicide or suicidal behaviour – just that an association was found between the two.
Most of the studies included in the review were observational, making it difficult to separate the effects of pollution from other factors that may influence mental health.
Factors such as socioeconomic deprivation, housing, physical health, and urban living could all contribute to the associations observed.
Despite these limitations, as ambient and household pollutants contribute to the deaths of around 6.7 million people globally per year, the researchers argue that environmental exposures deserve greater attention within suicide prevention.
Unlike many individual risk factors for suicide, pollution can potentially be addressed through population-level measures, including cleaner air policies and reductions in harmful environmental exposures, that have been shown to work in the past.
To encourage these changes, authors called for greater collaboration between environmental and mental health policy, suggesting that reducing pollution could have wider benefits for population wellbeing.
Further research is now needed to establish whether the relationships are causal and whether reducing exposure to pollutants can directly lower the risk of suicide and suicidal behaviour.
Reference
Jones SM et al. Environmental exposure and risk of death by suicide, attempted suicide and suicide ideation: a systematic review and meta-analysis. Journal of Epidemiology & Community Health. 2026. doi:10.1136/jech-2025-225491.
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