Living in polluted cities may make you more likely to be depressed or die by suicide ‘because toxic particles can damage your brain and mental health’
- For every 10ug/m3 increase in pollution, depression rises by 10% and suicide 2%
- Researchers reviewed studies into pollution and mental health in 16 countries
- It’s thought toxic particles emitted by cars, industry cause brain inflammation
People living in polluted areas are more likely to die by suicide or be depressed, research shows.
Scientists reviewed studies from 16 countries looking into the long-term impact of breathing in toxic airborne particles on mental health.
They found that as the level of pollution increased, so too did the rate of number of suicides and depression diagnoses.
It is thought the toxic particles emitted by cars and industry cause inflammation in the brain when they seep into the bloodstream after being inhaled, or affect levels of stress hormones – both of which have been linked to poor mental health.
Analysis showed average exposure to PM2.5 – the finest type of particulate matter – was 44 micrograms per metre cubed (ug/m3).
For every 10ug/m3 above this amount, there was around a 10 per cent increase in cases of depression and a two per cent rise in suicides.
Air pollution contains toxic chemicals which can cause swelling in the brain, contributing to the symptoms of mental health problems, according to research (stock image)
Scientists at University College London analysed data from nine studies into PM2.5 pollution and mental health in adults.
Pollution levels ranged wildly, from 114 and 97 in Delhi, India, and Dhaka, Bangladesh, to just six in Ottawa, Canada, and Wellington, New Zealand.
The World Health Organization (WHO) recommends pollution should be kept under 10ug/m3. But more than 90 per cent of countries exceed this level.
In UK cities, the average particulate matter level people are exposed to is 12.8ug/m3, according to estimates.
Breathing air in the UK’s most polluted areas is as bad as smoking almost 160 cigarettes a year, a charity has warned.
The British Heart Foundation said pollution in cities is a public health emergency and urged the government to bring in stricter rules to cut it down.
It found air quality is four times as bad in the worst area – Newham in East London – as it is in the cleanest – the Outer Hebrides in Scotland.
And almost all of the 25 areas with the most polluted air in the UK were in the English capital, with the exception only of Slough and Dartford.
Particles of pollution can seep into the body and cause life-threatening damage, raising the risk of stroke and heart attack, and contributing to lung diseases and cancers.
Others where the air is comparable to an average of 155 or more cigarettes each year included Westminster (157), Kensington & Chelsea (156), Islington (156), Waltham Forest (156) and Hackney (155).
Outside of London the worst affected areas were Slough in Berkshire (equal to 145 cigarettes), Dartford in Kent (144), Portsmouth (142) and Medway, Kent (142).
‘Air pollution is a major public health emergency and over many years it has not been treated with the seriousness it deserves,’ said the charity’s Jacob West.
The researchers estimate that lowering average air pollution levels to the WHO’s limit could reduce the risk of depression in British city-dwellers by roughly 2.5 per cent.
And they say that slashing global exposure to PM2.5 from 44ug/m3 to 25ug/m3 could result in a 15 per cent reduction in the risk worldwide.
The researchers also found evidence of a connection between air pollution and suicide. They said there was a noticeable spike on days when pollution was particularly bad.
The team found a two per cent heightened risk for each 10µg/m3 increase in the average PM10 level – given off by industry – over a three-day period.
Study lead author Dr Isobel Braithwaite said: ‘We already know that air pollution is bad for people’s health, with numerous physical health risks ranging from heart and lung disease to stroke and a higher risk of dementia.
‘Here, we’re showing that air pollution could be causing substantial harm to our mental health as well, making the case for cleaning up the air we breathe even more urgent.
‘We found quite consistent results across the studies we reviewed that analysed the relationship between long-term air pollution exposure and depression, even after adjustment for many other factors which could explain the association.
‘We know that the finest particulates from dirty air can reach the brain via both the bloodstream and the nose, and air pollution has been implicated in increased neuroinflammation, damage to nerve cells and to changes in stress hormone production, which have been linked to poor mental health.’
The researchers hope to follow up their study with further research into indoor air pollution and mental health risks.
The findings are published in Environmental Health Perspectives.
Suicide is one of the world’s major killers – 6,507 people in the UK took their own lives in 2018, with males aged 45 to 49 most at risk. The number was 45,000 in the US.
Approximately one in four people in the UK and US experience a mental health problem each year.
One in six report experiencing a common mental health problem such as anxiety and depression in any given week.
More than 80 per cent of the world’s urban population is breathing unsafe levels of air pollution.
Described as an invisible killer, it causes an estimated seven million premature deaths a year worldwide, according to the World Health Organisation.
Pollution is also fuelling increases in degenerative diseases such as Alzheimer’s and other forms of dementia, health experts fear.
Previous studies have found air pollution has a negative impact on students’ cognitive abilities.
Many pollutants are thought to directly affect brain chemistry in a variety of ways.
For instance, particulate matter from traffic and industry can carry toxins through small passageways and directly enter the brain.
WHAT HAVE RECENT STUDIES SHOWN POLLUTION CAN DO TO OUR BODIES?
CAUSE CHILDREN TO HAVE A LOW IQ: Researchers at the University of California, San Francisco, found in May 2019 that children born to mothers who live in polluted areas have an IQ that is up to seven points lower than those living in places with cleaner air.
CAUSE CHILDREN TO HAVE POORER MEMORY: Researchers at the Barcelona Institute for Global Health found boys exposed to greater levels of PM2.5 in the womb performed worse on memory tests by the time they are 10.
DELAY THE DEVELOPMENT OF CHILDREN: Youngsters who live less than one-third of a mile away from busy roads are twice as likely to score lower on tests of communication skills in infancy, found researchers at Eunice Kennedy Shriver National Institute of Child Health in April. They were also more likely to have poorer hand-eye coordination.
MAKE CHILDREN MORE ANXIOUS: University of Cincinnati scientists claimed pollution may alter the structure of children’s brains to make them more anxious. Their study of 14 youngsters found rates of anxiety was higher among those exposed to greater levels of pollution.
CUT YOUR CHILD’S LIFE SHORT: Children born today will lose nearly two years of their lives because of air pollution, according to a report by the US-based Health Effects Institute and the University of British Columbia in April 2019. UNICEF called for action on the back of the study.
RAISE A CHILD’S RISK OF AUTISM: Researchers at Monash University in Australia discovered youngsters living in highly polluted parts of Shanghai have a 86 per cent greater chance of developing ASD. Lead author Dr Yuming Guo said: ‘The developing brains of young children are more vulnerable to toxic exposures in the environment.’
CAUSE ASTHMA IN CHILDREN: Four million children around the world develop asthma each year because of road traffic pollution, a major study by academics at George Washington University estimated. Experts are divided as to what causes asthma – but exposure to pollution in childhood increases the risk by damaging the lungs.
MAKE CHILDREN FAT: University of Southern California experts found last November that 10 year olds who lived in polluted areas when they were babies are, on average, 2.2lbs (1kg), heavier than those who grew up around cleaner air. Nitrogen dioxide pollution could disrupt how well children burn fat, the scientists said.
LEAVE WOMEN INFERTILE EARLIER: Scientists at the University of Modena, Italy, claimed in May 2019 that they believe pollution speeds up ageing in women, just like smoking, meaning they run out of eggs faster. This was based on them finding almost two-thirds of women who have a low ‘reserve’ of eggs regularly inhaled toxic air.
RAISE THE RISK OF A MISCARRIAGE: University of Utah scientists found in January that pregnant women are 16 per cent more likely to suffer the heartbreak of a miscarriage if they live in areas of high pollution.
RAISE THE RISK OF BREAST CANCER: Scientists at the University of Stirling found six women working at the same bridge next to a busy road in the US got breast cancer within three years of each other. There was a one in 10,000 chance the cases were a coincidence, the study said. It suggested chemicals in the traffic fumes caused the cancer by shutting down the BRCA genes, which try to stop tumours growing.
DAMAGE A MAN’S SPERM: Brazilian scientists at the University of Sao Paulo found in March that mice exposed to toxic air had lower counts and worse quality sperm compared to those who had inhaled clean air since birth.
MAKE MEN LESS LIKELY TO GET SEXUALLY AROUSED: Scientists at Guangzhou Medical University in China found rats exposed to air pollution struggled to get sexually aroused. Scientists believe it may also affect men, as inhaling poisonous particles may trigger inflammation in blood vessels and starve the genitals of oxygen – affecting men’s ability to become sexually aroused.
MAKE MEN MORE LIKELY TO HAVE ERECTILE DYSFUNCTION: Men who live on main roads are more likely to have difficulty getting an erection due to exposure to pollution, a Guangzhou University in China study suggested in February. Toxic fumes reduced blood flow to the genitals, tests on rats showed, putting them at risk of developing erectile dysfunction.
RAISE THE RISK OF PSYCHOSIS: In March, King’s College London scientists linked toxic air to intense paranoia and hearing voices in young people for the first time. They said uncovering exactly how pollution may lead to psychosis should be an ‘urgent health priority’.
MAKE YOU DEPRESSED: Massachusetts Institute of Technology researchers found in January that that the more polluted the air, the sadder we are. Their study was based on analysing social media users in China alongside the average daily PM2.5 concentration and weather data where they lived.
CAUSE DEMENTIA: Air pollution could be responsible for 60,000 cases of dementia in the UK, researchers from King’s College London and St George’s, University of London, calculated last September. Tiny pollutants breathed deep into the lungs and enter the blood stream, where they may travel into the brain and cause inflammation – a problem which may trigger dementia.
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