Air pollutant exposure linked to heightened risk of death by suicide/suicidal thoughts
· Medical Xpressedited by Swati Mestri, reviewed by Robert Egan
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Exposure to air pollutants, especially small particulate matter (PM2.5 and PM10) and nitrogen dioxide (NO2), may heighten the risk of death by suicide and suicidal thoughts, suggests a pooled data analysis of the available evidence, published online in the Journal of Epidemiology & Community Health.
The findings underscore the need to consider environmental exposures as potentially modifiable risk factors in suicide prevention strategies, emphasize the researchers.
Globally, more than 720,000 people die by suicide every year, prompting the World Health Organization to develop a Mental Health Action Plan to reduce this global toll by at least a third between 2013 and 2030, they explain.
The interplay of individual, biological and contextual factors means that suicide prevention is a public health issue, they suggest.
But while the effect of environmental exposures on mental health outcomes, such as depression or anxiety, has been extensively studied, the potential role of environmental factors in the risk of suicide is less well understood.
How the review was built
To strengthen the evidence base, the researchers wanted to find out whether air, noise, light and water pollution and sociodemographic factors, such as sex and income, might influence the risk of death by suicide and suicidal behaviors.
They scoured research databases for relevant studies published in English between January 2010 and April 2024. Of an initial haul of 287 studies selected for full-text review, 45 met the eligibility criteria: 33 investigated death by suicide; 7, suicidal thoughts; and 5, attempted suicide.
Most studies looked at the effects of air pollution exposure (38); 3 looked at water pollution, 3 at noise pollution and 1 at light pollution.
The results of 29 studies were included in a pooled data analysis; 16 were included in a narrative review, which summarizes the existing evidence using text.
Air pollution showed the clearest link
The pooled data analysis showed that short-term exposure to PM2.5 (13 studies) and PM10 (7 studies) and long-term exposure to PM2.5 (6 studies) and NO2 (7 studies) were statistically significantly associated with the risk of death by suicide, attempted suicide and suicidal thoughts.
The synthesis of evidence from the narrative review showed potential positive associations with other air pollutants, including sulfur dioxide (SO2) and ozone (O3), as well as noise pollution.
Pooled data analysis wasn't possible for the effects of water and light pollution because of the limited number of studies and varying outcome measures; the narrative review findings for these exposures were inconsistent.
There were no clear associations between sociodemographic factors and the risk of death by suicide or suicidal behaviors.
Possible pathways in the brain
By way of an explanation for the findings, the researchers point out that air pollutants, including PM2.5, PM10, NO2, SO2 and O3, and water polluted with arsenic, lead, lithium or nitrate have been linked to neurological effects, including chronic inflammation and nerve damage, which can impair brain function and influence mood and stress resilience.
And it has been suggested that traffic and other environmental noise and light pollution increase stress levels through disruption of the body clock, they add.
Limits of the current evidence
The researchers acknowledge various limitations to their findings, including the small number of studies available on each respective outcome. The included studies also varied considerably in methodology and design.
But they nevertheless conclude, "These findings bring to attention the critical importance of recognizing environmental exposures as modifiable risk factors within suicide prevention efforts.
"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 well-being."
Publication details
Environmental exposure and risk of death by suicide, attempted suicide and suicide ideation: a systematic review and meta- analysis, Journal of Epidemiology and Community Health (2026). DOI: 10.1136/jech-2025-225491
Journal information: Journal of Epidemiology and Community Health
Key medical concepts
Nitrogen DioxideSuicidal ideation
Clinical categories
PsychiatryPsychology & Mental healthPreventive medicine Provided by British Medical Journal Who's behind this story?
Swati Mestri
Swati Mestri holds a bachelor's degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space. Full profile →
Robert Egan
Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →
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