Air pollution is linked to poor mental health outcomes, as well as specific mental disorders, in a research review by the University of Cambridge.
The findings show that poor air quality, both indoors and outdoors, may lead to depression, anxiety, psychoses, and perhaps even neurocognitive disorders, such as dementia.
Children and adolescents exposed to air pollutants at critical stages in their mental development were at the highest risk of significant future mental health problems.
The findings, published in the British Journal of Psychiatry, indicate that modifying exposure to poor indoor and outdoor air quality could impact rising levels of mental health disorders.
Air pollution and mental health are both significant global health challenges. The World Health Organization (WHO) state that air pollution is the single biggest environmental threat to human health, with an estimated that 4.2 million and 3.8 million premature deaths attributable to outdoor and indoor air pollution, respectively. Alongside the effects on cardiovascular and respiratory health, there is emerging evidence that exposure to air pollutants may lead to neurocognitive disorders and poor mental health.
The research aimed to conduct a rapid narrative review of existing research to assess the current understanding and highlight knowledge gaps where future research can address the intersection between mental health and levels of air pollution.
The researchers, who were part of the BioAirNet programme, looked at a broad range of pollutants, including bioaerosols- airborne particles which contain living organisms such as fungi, pollen or bacteria- heavy metal ions, inorganic particulate matter and gaseous pollutants. They examined how these air pollutants affected psychiatric, cognitive and neurodevelopmental pathways over a lifetime, from pregnancy and birth to adolescence and adulthood.
Evidence emerged that polluting air particles, including bioaerosols, are associated with poor mental health and specific mental health disorders such as depression, psychoses and anxiety. Air pollution exposure at key developmental periods for children and adolescents was observed to lead to more severe mental health outcomes later in life. In addition, long-term health conditions were observed to deteriorate with poor air quality, both indoors and outdoors.
Professor Kam Bhui from the psychiatry department at the University of Oxford said the research was ‘a vital public health priority’ as the world grapples with both air pollution and mental health challenges.
‘Our review shows that there is emerging evidence of links between poor air quality and poor mental health, as well as links to specific mental disorders. In particular, polluting air particles, including bioaerosols, have been implicated,’ Professor Bhui said.
Additional factors that increase the risk of air pollution affecting mental health include poor housing, overcrowding, poverty, a lack of green spaces, and a lack of access to support, carers or safe spaces.
Professor Bhui added: ‘We need more research to understand these webs of causation and to investigate a number of other critical knowledge gaps such as the mechanisms by which particles matter, and bioaerosols may cause and worsen health conditions. We need better ways to measure exposure to pollution and understand how climate change affects air pollution. We also call for more longitudinal studies to understand the effects on children and young people as they grow.’
