- In a meta-analysis of 29 studies, increasing exposure to fine and coarse particular matter was tied to increased risks for death by suicide, attempted suicide, and suicidal ideation.
- The researchers suggested that air pollution may trigger chronic inflammation and neurotoxicity, impairing brain function and reducing stress resilience and mood regulation.
- A narrative review of 16 studies showed that associations with other air pollutants and noise pollution were possible, but did not reach significance.
Exposure to air pollution showed positive associations with risks for death by suicide, attempted suicide, and suicidal ideation, according to a systematic review and meta-analysis.
Across 29 studies, each 10 μg/m3 increase in exposure to particles with a diameter of 2.5 µm or smaller (PM2.5) or 10 µm or smaller (PM10) was tied to increased risks for death by suicide, attempted suicide, and suicidal ideation:
- Short-term (<6 months) PM2.5 exposure: OR 1.01, 95% CI 1.00-1.03
- Short-term PM10 exposure: OR 1.01, 95% CI 1.00-1.02
- Long-term (>6 months) PM2.5 exposure: OR 1.53, 95% CI 1.14-2.05
PM2.5, also known as fine particular matter, comes from vehicle exhaust, power plants, wildfires, and indoor activities like cooking or burning candles. PM10, or coarse particulate matter, primarily comes from dust, dirt, and debris.
A 10-ppb increase in long-term nitrogen dioxide exposure was also linked to an elevated risk (OR 1.32, 95% CI 1.06-1.63), reported Sophie Marie Jones, PhD, of Queen’s University Belfast in Ireland, and colleagues in the Journal of Epidemiology & Community Health.
A narrative review of 16 studies showed that associations with other air pollutants (sulfur dioxide, ozone, and carbon monoxide) and noise pollution were possible, but did not reach significance.
Several pathways may explain the observed associations. Air pollution may trigger chronic inflammation and neurotoxicity, impairing brain function and reducing stress resilience and mood regulation, the researchers suggested.
“Our findings highlight that environmental exposures, particularly air pollution, may be one piece of a wider set of factors associated with suicidal thoughts and behaviors,” Jones told MedPage Today.
“Suicide is a complex issue, and there is no single explanation,” she noted. “Our findings should therefore not be interpreted as showing that any one environmental exposure causes suicide.”
Instead, she and her team hope the findings add to growing evidence that the environments in which people live affect their health and well-being. “Understanding these broader influences could ultimately help identify opportunities for prevention, alongside the important work that is already being done to support people experiencing poor mental health,” Jones said.
Previous research has suggested that environmental factors — including air, noise, light, and water pollution — may influence mental health outcomes such as depression and anxiety, though few studies have focused directly on suicidality. A 2025 analysis of Medicare data linked each higher quartile of PM2.5 exposure averaged over 5 years to a 7% higher risk of incident depression.
However, existing data are observational and no causality has been established, emphasized Jon Van Niekerk, MBChB, of the Royal College of Psychiatrists in London, in comments posted to the Science Media Centre website.
“Air pollution is closely associated with other factors which we know can influence mental health, including socioeconomic deprivation, urban living, physical health, and housing,” he wrote. “Although individual studies attempt to adjust for some of these factors, the findings may still be influenced by them.”
“The study provides further population-level support for reducing harmful air pollution, 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,” he noted.
For this systematic review and meta-analysis, the researchers reviewed 45 studies published between 2010 and 2024, 29 of which were included in the meta-analysis. Studies were conducted in general populations across Europe, North America, Asia, and South America.
Thirty-three studies investigated death by suicide, seven investigated suicidal ideation, and five investigated attempted suicide. Across exposure types, 38 examined air pollution, three examined water pollution, three examined noise pollution, and one examined light pollution.
Limitations in the available literature prevented definitive conclusions regarding water or light pollution.
Future research should assess the cumulative effects of these environmental exposures to better understand their combined influence on suicidal thoughts and behaviors, the authors suggested.
