Study finds suicide rate climbs within a week of air pollution events

New research in China suggests not only a link between air pollution episodes and suicide, but that as little as one week can separate the two events.

On a brighter note, the research also points out that in China – where 16% of the World’s suicides take place – efforts to improve air quality has saved over 45,000 lives that would have been lost to suicide.

The researchers describe these as: ‘additional’ suicides – deaths that would otherwise never have occurred had air quality not deteriorated.

China introduced its Air Pollution Prevention and Control Action Plan in 2013, following which annual average concentrations of PM2·5 fell by 33% and carbon monoxide by 28·2% over five years.

Research across 74 major cities found that in 2017, this improvement in air quality had led to 47,240 fewer deaths from related diseases than in 2013. 

It has also been noted that improved air quality has lead to a significant decline in suicide rates, leading to this new research, prompted by increasing evidence suggesting that air pollution may play a role in shaping suicide risk by altering brain function.

The research team examined the impact of thermal inversions, described by the European Environment Agency as an event when: ‘warmer air rises and acts as a lid trapping the colder air close to the ground. Pollution, including that from road traffic is also trapped, so the air layer closest to the ground becomes more and more polluted. This continues until the prevailing meteorological conditions change.’

Such inversions only last a matter of hours but the researchers found that their occurrence prompted an increase in suicide rates to peak within a week, declining thereafter. This, they say, is ‘consistent with neurobiological evidence that PM_2.5 influences emotional regulation and impulsive–aggressive behaviour.’

It was found that women over 65 were significantly more vulnerable than other members of society.

There has been a global fall in the number of recorded suicides and the researchers estimate that 10% of the decline in China is due to the efforts made to clean up the country’s air.