Through abundant factory emissions, vehicle exhaust pipes, incesticide mists, and tobacco smoke clouds, a blazing pink sun sets in Dhaka. The capital city is one of the most polluted in the world; in 2023, Bangladesh’s air quality index (AQI) was, on average, 16 times greater than the guidelines set by the World Health Organization (WHO).
Air pollution is an issue for urban and industrial hotspots around the world as society’s emissions fuel climate change. This causes temperature increases and fluctuations as well as weather extremities, affecting nature and life on Earth as a whole. Bangladesh serves as an example of this with the temperature gap between summertime heat waves and dry winters widening each year: In 2024, so far the highest temperature has been 43.7°C in Chuadanga and the lowest was 5°C in Tetulia.
However, air pollution also has direct repercussions on the physical health of individual inhabitants of highly-polluted regions such as the Dhaka metropolis. The impact of air pollution on the lungs and respiratory system has proved to be comparable with that of smoking cigarettes. For instance, some shared symptoms of pollutant exposure and cigarette consumption are shortness of breath, coughing, increased risk of stroke, lung cancer, and respiratory diseases.
Additionally, pulmonary function is compromised by high AQI as the inhalation of pollutants in the form of particulate matter and gases like ozone irritate the respiratory system and its linings from the nasal cavities to the bronchioles. Larger particles (PM10) specifically cause inflammation by penetrating the lungs and lodging themselves in the way of the capillary-alveoli barrier -- the barrier across which oxygen must diffuse from the lungs into the bloodstream. On the other hand, smaller particles (PM2.5) penetrate the lungs and are able to cross the barrier and enter the bloodstream, which allows them to harm nearly all major organs via the circulatory system.
Pollutants also terminate the cells that compose the epithelial tissue of the capillary-alveoli barrier, further reducing the capability to deliver oxygen to the body. Overall, increased pollutant concentration and duration of exposure aligns with increased health repercussions including risk of disease, respiratory inflammation, and lung capacity reduction.
The residents of Dhaka are especially susceptible to the health defects caused by air pollution since the densely populated city exceeds its capacity for urbanization and relies on a fabrication industry. This correlates with excessive combustion of fossil fuels.
Ambient (outdoor) pollution is avoidable to an extent by limiting time spent outdoors, especially exercise, but only if indoor pollution is low. Low indoor pollution can be obtained by using air purifiers, but poverty is prominent in Bangladesh: In 2022 18.7% of the population was below the poverty line. For most low-income households, air purifiers and proper insulation are not accessible or affordable, and household pollution may even be worse than ambient pollution due to poor ventilation partnered with incomplete combustion when fueling stoves and lights. Low-income individuals are also more likely to do physically intense labour outdoors, in factories, or in buildings lacking air purification.
Low-income residents had pulmonary function values that were 12.5% lower than the university students on average
This means that the city’s low-income population is the most susceptible to air pollution and the health risks associated with it. A clinical trial carried out by S Choudhury, MS Alam, and QM Begum collected various pulmonary function measurements values (vital capacity, forced vital capacity, expiratory volume) of Bangladeshi male residents in two different groups. One group being university students and office workers, and the other being low-income residents. The trial reported that low-income residents had pulmonary function values that were 12.5% lower than the university students on average. This discrepancy is particularly concerning because the low-income population of Dhaka is also the population with the least access to healthcare.
The clinical trial also reported that once adulthood is reached, pulmonary function values decrease with age. This supports the notion that longevity of the exposure to air pollution increases its impact on the body. Nevertheless, these impacts can present themselves as early as childhood and can harm lung function while a child grows, limiting the lungs’ development.
A study published in the Journal of Epidemiology and Community Health observed the pulmonary function of schoolchildren in China and found that for every 10μg/m3 increase in annual PM2.5 (smaller particulate matter) level, the annual forced vital capacity growth of the children’s lungs was reduced by 12.2mL. Hence, growing up in polluted environmental conditions can induce permanent harm, diminishing pulmonary capacity and capability in developmental stages so that such functions do not achieve their full potential once physical maturity is reached.
The reality is that air pollution is a threat to the health of Bangladesh and nations with similar environmental conditions and challenges. This threat can be reduced by improving working conditions, increasing air purification, and accessibility to healthcare. But the most effective way to confront the issue is by reducing emissions and air pollution itself with a more sustainable, healthier future.
Ann Kaydos-Daniels is a student at the American International School, Dhaka.
