Exposure to air pollutants may heighten the risk of death by suicide and suicidal thoughts, new research has found.
The research, published in the Journal of Epidemiology & Community Health, noted exposure to specific small particulate matter and nitrogen dioxide as particular risks for suicidal ideation.
Researchers said environmental exposure should be considered in suicide prevention strategies.
More than 720,000 people die by suicide each year globally, according to the World Health Organisation (WHO), which is aiming to reduce that number by at least a third globally as part of its Comprehensive Mental Health Action Plan 2013-2030.
RM Block
The WHO suggests that the link between individual, biological and contextual factors means suicide prevention should be considered a public health issue.
The authors of the study pointed out that environmental exposures and their link to depression and anxiety has been extensively studied, but their potential effect on the risk of suicide was less well understood.
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 behaviours.
They compared various research databases between January 2010 and April 2024.
Thirty-three studies investigated death by suicide, seven examined suicidal thoughts, and five, attempted suicide.
Most studies looked at the effects of air pollution exposure (38), three looked at water pollution, three at noise pollution, and one at light pollution.
The researchers pointed out that air pollutants (including PM2.5, PM10, NO2 SO2, and O3) as well as 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.
It has been suggested that traffic and other environmental noise and light pollution increase stress levels through disruption of the body clock, they explained.
The researchers acknowledged limitations to their findings, including the small number of studies available on each respective outcome.
However, they concluded: “These findings bring to attention the critical importance of recognising 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 wellbeing.”
