Between 2018 and 2021, Dhaka was ranked the 2nd most polluted city in the world. But what are the consequences?
Published : 02 Jul 2023, 07:30 PM
Dhaka, the capital city of Bangladesh, has experienced rapid urbanisation and industrialisation in recent years, leading to a significant rise in air pollution levels. Between 2018 and 2021, the city ranked as the second most polluted in the world. The true implications of this on the city’s residents must be understood.
Air pollution encompasses a wide range of pollutants, including gases, metals, chemical compounds, and particulate matter (PM). Among these, PM has the most detrimental effects on physical and mental health. Both human activities and natural processes contribute to the presence of PM in the atmosphere. Factors such as windblown dust, wildfires, burning of fossil fuels (such as automotive exhaust), industrial activities, and large-scale agricultural operations contribute to the high levels of PM found in Dhaka.
Particulate matter with a diameter of less than 2.5 micrometres, known as fine particulate matter, can easily be inhaled and absorbed into the circulatory system. This means fine particulate pollution poses a greater hazard compared to larger particles.
High levels of air pollution can result in respiratory tract infections, depression, and various other health issues. The most vulnerable groups, as highlighted in a 2022 World Bank report on the health impacts of air pollution, include young children under the age of five, the elderly, and individuals with other comorbid conditions such as diabetes, heart disease, or respiratory problems.
According to that same World Bank report, air pollution was the second largest cause of death and disability in Bangladesh in 2019, accounting for around 3.9 to 4.4 percent of the country's GDP.
While the impact of air pollution on physical health is commonly emphasised, its impact on mental health is often overlooked. Numerous studies have demonstrated a significant link between air pollution and mental health issues. Individuals exposed to polluted air experience changes in the brain regions responsible for emotions, making them more susceptible to problems like anxiety and depression compared to those breathing clean air.
Air pollution has also been associated with inflammation and oxidative stress in the brain, which can negatively affect cognitive abilities and even cause neurological damage. Additionally, air pollution is linked to a decreased attention span, and poorer memory, and learning skills, as well as an increased risk of developmental issues in children and adolescents.
Alarmingly, the World Bank warns that a 1 percent increase in exposure to PM2.5 above the World Health Organization's Air Quality Guidelines (AQG) is associated with a 20 percent higher risk of depression.
The report also highlights that areas with heavy traffic and construction exhibit the highest rates of depression (13.7 percent). Among the residents of these areas, 13.7 percent of women and 11.8 percent of men report experiencing depression. These trends align with findings from other countries, which show a rise in depression among women and an increase in depression with age.
Collectively, these findings suggest a potential vulnerability to increased levels of depression as air quality worsens. Spending time outdoors is typically associated with well-being and reduced adverse mental health outcomes. In Bangladesh, both exposure to PM2.5 and the amount of time spent outdoors contribute to depression.
A systematic review from 2019 found significant correlation between PM2.5 and depression, anxiety, and other mental health issues.
"With more evidence showing a pronounced impact of climate change on physical and mental health, Bangladesh needs to build on its success in adaptations to ensure a stronger health system that averts outbreaks of emerging climate-sensitive diseases," said Mercy Tembon, the World Bank country director for Bangladesh and Bhutan, in 2021.
As climate change intensifies and carbon emissions remain unregulated, air pollution will continue to worsen. Given the available data and statistics, it is clear that the youth of Dhaka are highly vulnerable to air pollution, which will not only affect their physical health, but also their mental wellbeing.
REFERENCES
Raza, Wameq and Mahmud, Iffat. ‘Breathing Heavy: New Evidence on Air Pollution and Health in Bangladesh – Headline Messages’. World Bank. 2022.
World Bank. ‘Bangladesh: Climate Change is Affecting Health and Mental Wellbeing’. 2021.