Air Pollution may increase suicide risk; study links PM2.5, PM10 and NO2 to suicidal behaviour

PTC Web Desk: Exposure to air pollution may be associated with a higher risk of suicide, suicide attempts and suicidal thoughts, according to a review of existing research. The study identified PM2.5, PM10 and nitrogen dioxide (NO2) among the pollutants most consistently linked with the risk.

Researchers from Queen’s University Belfast analysed findings from 29 studies that examined the relationship between exposure to air pollution and suicidal behaviour. Their findings were published in the Journal of Epidemiology and Community Health.

The researchers said the results suggest that environmental factors that can potentially be reduced should also be considered when developing strategies to prevent suicide. They stressed that suicide prevention should not be viewed only through the lens of mental health, as individual, biological, social and environmental factors can interact in complex ways.

PM2.5 and PM10 linked to short-term risk

The statistical analysis found a significant association between short-term exposure to PM2.5 and PM10 and an increased risk of suicide and suicidal behaviour. Longer-term exposure to PM2.5 and NO2 was also associated with higher risks of suicide, suicide attempts and suicidal thoughts.

Researchers noted that some other pollutants, including sulphur dioxide and ozone, may also be linked to suicidal behaviour, although the evidence for these pollutants was less consistent.

PM2.5 refers to very fine particles that can penetrate deep into the respiratory system, while PM10 consists of larger airborne particles. Nitrogen dioxide is commonly produced by combustion processes, including vehicle traffic and other sources.

How pollution could affect the brain

The researchers pointed to previous evidence suggesting that exposure to certain environmental pollutants can affect the nervous system. They also noted that contaminated water containing substances such as arsenic, lead, lithium or nitrate has been associated with adverse neurological effects.

Such exposure may contribute to processes, including inflammation and damage to the nervous system, which can affect brain function, mood and the body's ability to respond to stress.

However, the researchers stressed that the relationship between pollution and suicidal behaviour is complex. Factors such as mental health, personal circumstances and biological differences can also influence suicide risk.

More research needed

The researchers said considerable work has already examined links between air pollution and conditions such as depression and anxiety, but comparatively less research has focused specifically on suicide and suicidal thoughts.

Professor Ben Mullins of the School of Population Health at Curtin University in Australia, who was not involved in the study, said the review is among the early broad analyses examining the relationship between air pollution and suicide.

Mullins noted that several pollutants, particularly some metals, are already known to affect the nervous system and have been associated with mental health conditions such as depression and anxiety. He said the findings therefore add to existing evidence suggesting a possible connection between environmental pollution and mental health outcomes.

ALSO READ | Canada study visa rules change: Students must show more funds from September 1