Air pollution now linked to hospital admissions for mental health, study finds

New research has identified a link between air pollution and an increased risk of hospital admissions for mental illnesses.

Previous studies tended to focus more on physical health, and on deaths rather than hospital admissions, the researchers said.

Now scientists from St Andrews University have found someone exposed to air pollution over a long period of time is more likely to be admitted to hospital for mental health and behavioural disorders.

They called for stricter environmental protections to benefit millions of people and free up hospital resources.

The St Andrews team analysed data from Public Health Scotland for the prevalence and impact of four key air pollutants, which are associated with road traffic and heavy industry.

The large-scale study included more than 200,000 people in Scotland, representing 5% of the Scottish population.

Sulphur dioxide had the strongest link with hospital admissions for respiratory disease, while nitrogen dioxide was associated with a higher number of hospital admissions for mental illness/behavioural disorders.

Cumulative exposure to two other pollutants, PM10 and PM2.5, was also associated with higher rates of hospital admissions for cardiovascular, respiratory, and infectious diseases.

The study, published in the journal BMJ Open, adds to an emerging body of evidence about the impact of dirty air on mental health.

Another paper published in May identified a link between indoor air pollution and depression.

Last year Oxford University scientists also found exposure to air pollutants could lead to depression, anxiety, psychoses, and even neurocognitive disorders like dementia.

Dr Mary Abed Al Ahad, the lead author of the new study, said more measures like low-emission zones or shifting to electric vehicles would help protect people's health and reduce the burden on hospitals.

"Policies and interventions on air pollution through stricter environmental regulations, long term planning, and the shifting towards renewable energy could eventually help ease the hospital care burden in Scotland in the long term," she said.

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The ultra low emission zone in London (ULEZ) has helped reduce the concentration of nitrogen dioxide by 24% in inner London, 53% in central London and 21% in outer London, according to the Greater London Authority

Isabella O'Dowd, head of climate at WWF, said switching from fossil fuels to electric vehicles was a "win-win for climate and human health".

She added: "Pollution from cars and trucks causes the premature deaths of twice as many people as road accidents, and now this new research shows it affects mental health as well.

"The science has never been clearer, we need to invest in electric vehicles, public transport and charging networks faster than ever to protect people and nature."