When it comes to air pollution, high levels of air pollution negatively impact a variety of medical illnesses such as respiratory illnesses, eczema, and more. The effects have been studied extensively and is a well established fact that certain air pollutants have a deleterious effect on health. However, much less is understood about air pollution’s effect on psychiatric illnesses.
A recently published paper in Nature Sustainability provided a compelling narrative on how improving air quality in China led to a noticeable decline in suicide rates. This groundbreaking finding offers a glimmer of hope, suggesting that environmental policies and concerted efforts to cleanse the air can yield significant mental health benefits.
Improving Air Quality to Reduce Depression and Suicide Rates
Globally, an estimated 5% of adults suffer from depression. As of 2016, there was an estimated global suicide rate of 10.5 per 100,000 people. In South-East Asia, 86 million people suffer from depression, and more than half of the suicides that occur globally every year come from South-East Asia and the Western Pacific regions. At the same time, many regions in Asia experience high levels of air pollution due to rapid industrial growth. Countries like Bangladesh and Pakistan have some of the poorest air quality in the world. With new studies linking air quality and mental health, additional interventions can consider the potential role of environmental factors, especially air quality, in managing depression and reducing suicide rates. This calls for governments and policy-makers to aid in creating a cleaner environment.
The link between air quality and mental health
In recent years, the topics surrounding air pollution have moved beyond just focusing on physical health issues. Research on the impact of air quality has started exploring the less familiar area of mental health. The discovery that air pollution can significantly affect our mental health is crucial information for healthcare professionals. It highlights the need for them to consider this factor in addition to regular treatments or health interventions when advising patients.
The Unseen Enemy
The air pollutants we inhale, particularly fine particulate matter (PM 2.5), have significant effects on physical ailments and can also affect our brain’s structure and function, leading to psychiatric disorders. One of the earliest research published in 1979 was one of the first to suggest a link between air pollution and psychiatric illness. The authors found that levels of air pollutants such as carbon monoxide and ozone highly correlate with the admission rate of psychiatric patients in St Louis, Missouri (USA). They hypothesised that air pollution may affect the central nervous system and alter the neurotransmitter balance, leading to mood and behavioral changes. This paper inspired further research on the effects of air pollution on mental health.
Over the years, research has increasingly shown that air pollutants affect the brain. A systematic review focusing on the effects of air pollution on mental health and brain structure/function found that exposure to air pollutants is associated with increased symptoms of anxiety and depression. This association is also linked to structural and functional changes in the brain, particularly in regions implicated in controlling mood and emotion, such as the hippocampus, prefrontal cortex, and amygdala, thus increasing the risk of psychopathology. Another study using two large datasets from the US and Denmark found that environmental factors, especially air pollution, contribute towards the onset and development of psychiatric disorders, including bipolar disorder, major depression, personality disorder, and schizophrenia.
Insights from the East
Asia, with its rapid industrial growth and urbanisation, has become a pivotal region for studying the effects of air pollution on mental health. Adding on to support the previous studies, research shows a similar trend is observed in Asia. Notably, two studies from China and Korea have added depth and dimension to our understanding of this issue.
In South Korea, analysing over 4,000 suicide cases between 2004 and 2006, the study revealed significant association between short term ambient particulate matter exposure and increased suicide risk, especially for females, the elderly, and those with low education. The researchers found a 9.0% to 10.1% increase in suicide risk related to a corresponding increase in particle matter.
A Ray of Hope
Complementing these findings, a new study in China proved that improving air quality significantly declined suicide rates. By meticulously analysing data over several years, researchers found a clear, inverse relationship between air quality improvements and suicide incidences. This statistical study estimates that PM2.5 reductions under China’s Air Pollution Action Plan prevented 13,000–79,000 (95% confidence interval) suicides over 2013–2017. Therefore, environmental policies and concerted efforts to cleanse the air can yield significant mental health benefits.
These studies serve as a reminder of the urgent need for countries across Asia and the globe to address air pollution as a multifaceted health hazard and emphasise the importance of considering environmental risk factors, including air pollution, in understanding and addressing the causes of psychiatric disorders.
The Role of Healthcare Professionals
Healthcare professionals are on the frontline when it comes to battling the repercussions of air pollution on mental health. Armed with these insights, here are some ways how they can make a difference:
Educating Patients
Patients can be informed about the risks associated with air pollution. This includes advising vulnerable groups on minimising exposure to particulate matter and implementing protective measures at home, like air purifiers or monitoring air quality indexes to plan outdoor activities.
Advocacy for Clean Air
Healthcare professionals can be advocates for stringent air quality regulations. By supporting policies targeting vehicle and industry emissions, they can influence legislative changes for a cleaner, healthier environment. Healthcare facilities are important places of recovery for patients. By adopting sustainable practices and improving air quality within the premises, these institutions can take a big step towards environmental stewardship in the community.
Community and Public Health Initiatives
Healthcare professionals can collaborate with urban planners, environmental scientists, and policymakers to develop strategies that address the causes of pollution and mitigate its health impacts. Together with other professionals, initiating public health campaigns and educational workshops can raise awareness about the dangers of air pollution, especially the lesser-known devastating impact on mental health.
Engaging in Research
There are continuing efforts in research on the impacts and causes of air pollution on mental illnesses, therefore to obtain a solid evidence base, healthcare professionals can actively contribute and collaborate in research. Whether it is participating in epidemiological studies or clinical trials, their involvement can deepen our understanding of air pollution’s impacts and aid in developing effective interventions and solutions.
Looking Forward
The journey towards understanding and mitigating the impacts of air pollution on mental health is ongoing. The studies from China and Korea are but two pieces of a larger puzzle, signalling the urgent need for global attention to this issue. Healthcare professionals stand at the vanguard, equipped with the knowledge and tools necessary to protect and enhance public health in the face of air pollution.
References
Zhang, P., Carleton, T., Lin, L., & Zhou, M. (2024). Estimating the role of air quality improvements in the decline of suicide rates in China. Nature Sustainability. https://doi.org/10.1038/s41893-024-01281-2
Kim, C., Jung, S. H., Kang, D. R., Kim, H. C., Moon, K. T., Hur, N. W., Shin, D. C., & Suh, I. (2010). Ambient particulate matter as a risk factor for suicide. American Journal of Psychiatry, 167(9), 1100–1107. https://doi.org/10.1176/appi.ajp.2010.09050706
Strahilevitz, M., Strahilevitz, A., & Miller, J. E. (1979). Air pollutants and the admission rate of psychiatric patients. American Journal of Psychiatry, 136(2), 205–207. https://doi.org/10.1176/ajp.136.2.205
Zundel, C. G., Ryan, P., Brokamp, C., Heeter, A., Huang, Y., Strawn, J. R., & Marusak, H. A. (2022). Air pollution, depressive and anxiety disorders, and brain effects: A systematic review. Neurotoxicology, 93, 272-300. https://doi.org/10.1016/j.neuro.2022.10.011
World Health Organization. (n.d.). Depression Factsheet AS. Retrieved from https://cdn.who.int/media/docs/default-source/searo/mhs/2.-depression_factsheet-2017_sear.pdf?sfvrsn=2edb51fe_5.
World Population Review. (2024). Suicide Rate by Country 2024. Retrieved from https://worldpopulationreview.com/country-rankings/suicide-rate-by-country.
World Population Review. (2024). Depression Rates by Country 2024. Retrieved from https://worldpopulationreview.com/country-rankings/depression-rates-by-country.
